2»

..and here is the relevant info:

4 - 60 Watt panels @ 12 v
2 - 75 watt panels @24 v
8 - 6v trojan batteries ((108 min @ 75amps) wired for 12 v)
2 - 2 sunsaver 10A controllers ( 12 v )
1 - 30 A charger controller ( 12 v )

I have the 4 12v and the 2 24v, so if I put all the 12v in a series I would have 48v, could that go into a 30A charge controller?

Yes, no, it depends... Yes, trying to be funny...

When you connect panels (or batteries) in parallel, the voltage remains the same and the current adds. When you put panels in series, the voltage adds, and the current remains the same (assuming panels are identical).

Your Morning Star controller (30 amp) does not support 48 volts--only 12 and 24. So, it will not work for what you want to do... You would have to get the 15 amp 48 volt version (in this product line).

A PWM type controller simply lets all of the panels amps through to the batteries (assuming the panel voltage is high enough, and the batteries are somewhat discharged). You can put 48 volts of panels on a 12 volt battery bank--but it would be a tremendous waste of power (and, may destroy the controller if the input voltage is too high). For a PWM controller (just random numbers as example):

P=15 volts * 10 amps = 150 watts into the battery
P=48 volts * 10 amps = 480 watts available, but only 150 watts into the battery

You can get a MPPT (maximum power point tracking) solar charge controller that can convert 48 volts @ 10 amps into, approximatly, 12 volts @ 40 amps (they are sort of the DC equivalent of a variable AC transformer). However, these controllers are more expensive, have more functions, and are many times better for the installation (more power collected, better battery charging, work better over a wider temperature range).

The problem with a mix of panel models and controller models--is that it can be confusing how best to connect them all together without spending extra money, or throwing money away on wrong equipment.

For your case, if you want to use the 24 volt panels, then you are sort of left with wiring your batteries into a 24 volt battery bank (+ wiring your 12 volt panels into 24 volt strings) and using 24 volt controller(s), or buying a MPPT controller which is capable of down converting your 24 volt panels into 12 volt output.

By the way, you will need to check the Vmp of your panels... Many "24 volt" panels are not really Vmp=32+ volts -- which is needed to charge a 24 volt battery bank.

I am sorry, it is difficult to try and tie everything together with one short, concise post.

In the end, what is it that you want--12 volt battery bank, 24 volt battery bank, 48 bank or what? And how much power (watt*hours) per day do you need / want to pay for (in panels, charge controllers, batteries, etc.). Once you have that defined, it is much easier to do the "upstream" side of the design.

And, exactly, what controllers/solar panels (model numbers and/or specific Vmp/Imp ratings for panels) do you have... Once you have the batteries and the panels defined, then either try and fit the charge controllers in between or look at other options.

Otherwise, this gets to be a little bit more like placing the cart before the horse.

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset

..I can do the panels as 12v..I think I had the MPPT in my head. As for the 24V panels I will just leave them out for now and use the 12v panels.

So, I can do the 12v into the charge controller and keep the 24v on the backburner for now.

So, 12v into the charge controller, 12v for the battery pack and a 12v ProSine inverter..should be good to go...

Until I open up the back of the panels and have to wire those up in parallel!

Once again, thanks for the info..very helpful!

I will take some pictures of the components and post up to make sure I am not going to mess anything up..stay tuned!

You don't have to put the 24 volt panels in storage--if you can swing this MPPT controller for ~\$234:

Morningstar SunSaver MPPT Solar Charge Controller

Arguably, about the best "small" (15 amp max, 12 or 24 volt battery system) MPPT controller out there... Has a nice computer interface (need to purchase the interface separately?) that you can play and learn with.

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
• Solar Expert Posts: 1,989 ✭✭✭

Looks like our host here doesn't carry the meterbus adapter, so I hope its OK to link to what BB is describing

And with this adapter you can run Morningstar's MS-View or freeware like my SC-View

http://www.solar-guppy.com/forum/sc-view-morningstar-sunsaver-mppt-pc-monintoring-software-t634.html

• Solar Expert Posts: 5,436 ✭✭✭✭
jacobs wrote: »
Interesting....I've probably seen close to a hundred gas refrigerators of all makes and sizes, new and old, (including a huge 1957 double door Servel) installed and never seen any provisions for outside venting on any of them. Since they weren't vented outside that means 99%+ efficiency or like I said before "free refrigeration" in the winter.

FYI to everyone!

Several people a year on average kill themselves with CO poisoning every year! It usually happens with older propane fridges that are not burning very well, in (semi) enclosed spaces. If you run ANY propane fridge, if you don't (can't?) vent it to the outside, at the very LEAST invest ~\$20 in a CO detector.

Most modern gas fridges come with either a direct vent kit that will vent out the back wall of a building (or RV), or a length of steel flex pipe through a small thimble through the wall.

Some of the Danbys and Counsels sold in Canada have an integrated direct vent kit, but most of the Servels/Dometics you have to provide your own vent. Some of the Danbys, Sibres, and Counsels have an integrated CO monitor that will turn off the flame if it detects serious amounts of CO.

The worst offenders are the older Klixon type Servells. They were (still are) great fridges, but they are prone to burning poorly if rust and stuff falls down the flue and onto the burner. They are also big fridges that stay at full flame 24/7 so they potentially put out lots of CO2 when they are burning poorly. If you have an old Servel or similar fridge, you can vent it to the outside using a what ever length of ~3" diameter tin stove pipe to get it to vent to the outside.

I would never allow anyone to sleep in a building with an unvented fridge with out a GOOD CO monitor.

Tony

And to add to the Holiday Warnings about Carbon Monoxide poisoning, a local article about a rental home in foreclosure using a generator in the basement because their electrical power was cut off a couple days ago (in the middle of the San Francisco Peninsula):
( 12-18-2008 ) 11:45 PST REDWOOD CITY -- All eight people poisoned by carbon monoxide from a gas generator running in a home near Redwood City where the power had been cut off are expected to recover, authorities said today.

Three children and three adults who lived in the home on the 200 block of Fourth Avenue were treated at Stanford Medical Center and released, Menlo Park fire Inspector Jon Johnston said this morning. Two children who were poisoned more severely Wednesday evening were still at Kaiser Medical Center in Redwood City but will be released soon, he said.

The children and adults were among 12 members of an extended family and friends who were renting in the home, located in an unincorporated part of San Mateo County, said Francisco Carrillo, a resident who was not among those poisoned. Authorities said the home was in foreclosure proceedings.

Pacific Gas and Electric Co. cut off power to the house Tuesday, so residents were powering electrical appliances, including a television and a string of Christmas lights, with a generator in a basement with inadequate ventilation, authorities said.

Around 8:30 p.m. Wednesday, people in the house started vomiting and passing out, Carrillo said.

"Everybody was inside watching TV and listening to music," he said. "Everybody got sick at the same time. They didn't smell anything. Everybody was throwing up."
...
-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
• Solar Expert Posts: 10,300 ✭✭✭✭

thx,
what pvs are they that are 75w and 24v as somebody just recently asked if there are lower wattage 24v pvs?

sg,
no problem.

bb,
in addition to what you said on the co2 detector people should know that such items like generators that unless they are specifically made to be used indoors that they should never be used indoors. many don't realize what we consider to be common sense not to do that as they are new to it and ignorant of the hazards involved. that reminds me of my niece that decided she wanted to have a bbq indoors. yes, she's blond, but very lucky to be alive after such ignorance.
• Solar Expert Posts: 5,436 ✭✭✭✭

Bill,

And those were the lucky ones!!! The unlucky ones are the ones that go to sleep and never wake up!!

As we here all know, but far too many people don't know, never, ever, ever run any engine in the house, including an attached garage. Never, ever, ever, burn a fuel burning appliance in the house UNLESS it is designed and approved for such burning, and then only as designed! Using a gas oven for a source of heat is a bad idea, even though the oven is approved to be burned indoors. The difference is that a closed oven cycles on and off such that it isn't always producing C0 and depleting O2. Remember, all fuel burnig devices, engines, fridges, barbques, candles, heaters, lamps etc, etc, not only put out C0, but also depletes O2! Combine low O2, and high C0, add in some sleepiness, perhaps some booze, and you have a recipe for death!

Do yourself a favor, and go buy a number of CO detectors for people that are at risk of making a mistake for a present! Cheap, and you may never know the thanks from the lives you save.

Tony.

I don't want to sound like a Nervous Nellie about all the "thou shall not" do labels that are on everything, but this is important. (The "best thou shall not" label I ever saw was on a hunters toilet seat. The toilet seat fit into the receiver type trailer hitch, giving the user a nice place to sit while answering the call of nature. The label read "Not for use while the vehicle is in motion!")
• Solar Expert Posts: 9,583 ✭✭✭✭✭

One note about CO detectors, the element in them, has a finite lifetime of 3-5 years, unlike a smoke alarm.
Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,

• Solar Expert Posts: 741 ✭✭
mike90045 wrote: »
One note about CO detectors, the element in them, has a finite lifetime of 3-5 years, unlike a smoke alarm.
Can you sight a source for this?? That is because I have 3 First Alerts CO/Smoke detectors. They are about 4-5 years old.

Yes, I too have seen older CO alarms with the warning of something like a 5 year life--I cannot find any details--but from First Alert:
What it the typical carbon monoxide detector life? How long will a CO alarm last?

A First Alert® carbon monoxide detector life span is warranted for 5 years. After 5 years any detector should be replaced with a new CO Alarm. Alarms may have an actual life span that is shorter due to environmental conditions and may need to be replaced sooner. Test them weekly and if a problem arises while still under warranty, please call for a replacement. Batteries should be replaced as needed for those alarms requiring them.
From the always reliable Wikipedia:
There are three types of sensors available and they vary in cost, accuracy and speed of response.[5] All three types of sensor elements typically last from 3 to 5 years. At least one CO detector is available which includes a battery and sensor in a replaceable module. Most CO detectors do not have replaceable sensors.
...
Biomimetic
A biomimetic (chem-optical or gel cell) sensor works with a form of synthetic hemoglobin which darkens in the presence of CO, and lightens without it. This can either be seen directly or connected to a light sensor and alarm.

Electrochemical
A type of fuel cell that instead of being designed to produce power, is designed to produce a current that is precisely related to the amount of the target gas (in this case carbon monoxide) in the atmosphere. Measurement of the current gives a measure of the concentration of carbon monoxide in the atmosphere. Essentially the electrochemical cell consists of a container, 2 electrodes, connection wires and an electrolyte - typically sulfuric acid. Carbon monoxide is oxidised at one electrode to carbon dioxide whilst oxygen is consumed at the other electrode. For carbon monoxide detection, the electrochemical cell has advantages over other technologies in that it has a highly accurate and linear output to carbon monoxide concentration, requires minimal power as it is operated at room temperature, and has a long lifetime (typically commercial available cells now have lifetimes of 5 years or greater). Until recently, the cost of these cells and concerns about their long term reliability had limited uptake of this technology in the marketplace, although these concerns are now largely overcome.

Semiconductor
Thin wires of the semiconductor tin dioxide on an insulating ceramic base provide a sensor monitored by an integrated circuit. CO reduces resistance and so allows a greater current which if high enough will lead to the monitor triggering an alarm. The power demands of this sensor means that these devices can only be mains powered.
And here is more than you will ever want to know about CO detectors (lots of good information--except useful stuff like brand name / model of detectors that failed testing). From the long PDF file (free to download):
The final period is that in which the detectors literally “wear-out”. The causes of wear-out are numerous, including sensor drift, exposure-related degradation, and the depletion of chemical reagents. If the sensing technology is sufficiently well matched to the application and the detector well designed, this period occurs beyond the lifetime required by the consumer.
From the above report, it appears that a minimum of 3 year lifetime is assumed (required?) by the UL standard. And given that the popular battery backed units use chemical based detector (fuel cell / battery like detector)--it is pretty apparent that a limited life is all that can be expected...

Also from the report, if you have a very low relative humidity (approaching 5%), then no current CO detector (as of 2002 report date) will work to specification. 50% RH most detectors will reliably detect dangerous amounts of CO...

In the end, after reading around--I would not trust a consumer CO alarm with my life. They are not reliable and one is much better served by ensuring that CO producing devices are never inside the home (generators, cars idling in a garage)--and that if you have 20+ year old furnaces and/or concerns about any gas/oil/fuel burning indoor vented appliances, that you have them checked out by a professional.

From some numbers that come up in Google--home based CO poisoning deaths (excluding people dying in cars from CO) are around ~170 per year, and around ~50 of them are associated with running a generator in/around a home.

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
• Solar Expert Posts: 72 ✭✭
icarus wrote: »
FYI to everyone!

Several people a year on average kill themselves with CO poisoning every year! It usually happens with older propane fridges that are not burning very well, in (semi) enclosed spaces. If you run ANY propane fridge, if you don't (can't?) vent it to the outside, at the very LEAST invest ~\$20 in a CO detector.

Most modern gas fridges come with either a direct vent kit that will vent out the back wall of a building (or RV), or a length of steel flex pipe through a small thimble through the wall.

Some of the Danbys and Counsels sold in Canada have an integrated direct vent kit, but most of the Servels/Dometics you have to provide your own vent. Some of the Danbys, Sibres, and Counsels have an integrated CO monitor that will turn off the flame if it detects serious amounts of CO.

The worst offenders are the older Klixon type Servells. They were (still are) great fridges, but they are prone to burning poorly if rust and stuff falls down the flue and onto the burner. They are also big fridges that stay at full flame 24/7 so they potentially put out lots of CO2 when they are burning poorly. If you have an old Servel or similar fridge, you can vent it to the outside using a what ever length of ~3" diameter tin stove pipe to get it to vent to the outside.

I would never allow anyone to sleep in a building with an unvented fridge with out a GOOD CO monitor.

Tony

The biggest problem with carbon monoxide and the old Servels and gas Whirlpools are people trying to use a natural gas frig on propane. The are easy to convert but you must know what you are doing. The only other problem is as stated.... a dirty flue which is very easy to clean. When properly adjusted and maintained, they are extremely clean burning. They are as clean burning as a gas kitchen range. An old Servel or Whirlpool will outlast any of the new cheaply made gas refrigerators. BTW, Whirlpool purchased the Servel company in 1957 and continued making the same gas refrigerator with very few changes for several years. Burners are identical and interchangeable between the two makes.

Servels with operating controls DO NOT "stay at full flame 24/7". There is a minimum and a maximum flame adjustment on the control and when operating, the refrigerator cycles back and forth between the two. If this doesn't occur, the refrigerator section will freeze solid.

If someone wants to use one of these refrigerators they should either locate someone familiar with servicing them or purchase a service manual. Service manuals are frequently sold on eBay.
• Solar Expert Posts: 5,436 ✭✭✭✭
jacobs wrote: »
The biggest problem with carbon monoxide and the old Servels and gas Whirlpools are people trying to use a natural gas frig on propane. The are easy to convert but you must know what you are doing. The only other problem is as stated.... a dirty flue which is very easy to clean. When properly adjusted and maintained, they are extremely clean burning. They are as clean burning as a gas kitchen range. An old Servel or Whirlpool will outlast any of the new cheaply made gas refrigerators. BTW, Whirlpool purchased the Servel company in 1957 and continued making the same gas refrigerator with very few changes for several years. Burners are identical and interchangeable between the two makes.

Servels with operating controls DO NOT "stay at full flame 24/7". There is a minimum and a maximum flame adjustment on the control and when operating, the refrigerator cycles back and forth between the two. If this doesn't occur, the refrigerator section will freeze solid.

If someone wants to use one of these refrigerators they should either locate someone familiar with servicing them or purchase a service manual. Service manuals are frequently sold on eBay.

I have had several old Servels over the years (Still do, but don't use them) including several kerosene types. I may be mistaken, but I don't think any of the 50's vintage LP fridges had an automatic adjusting flame. There is an flame adjustment, but no thermostat control for it. The trick was to get the cabinet cold, then slowly turn down the flame over a period of a few days, with a fridge thermometer as a guide, until you got to the desired temp. The problems that I routinely encountered with these units were rust and soot causing the burner to burn dirty.

I agree with you, that properly adjusted, they burn as clean as any gas range. The problem is with users who either don't know how to check them or fail to check them regularly.

I stand by my previous statement: I wouldn't allow anyone to sleep in a small building with an unvented gas fridge burning WITHOUT a C0 monitor.

Tony

PS. I don't know if the newer versions of the Servels C1960+, were any different. I think that Servel and Dometic are one company now, but it seems things keep changing. I know nothing about Whirlpool gas fridges.

Why would you change a LP fridge to Nat Gas? It seems if you have Natural Gas available you would also have grid power available, and therefore be using something more efficient than an old Servel/Whirlpool.

I see I forgot to add the pointer to the Website PDF report about CO Detectors and their test report. I have updated my previous post, and here it is again:

Evaluating the performance of residential CO Alarms

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
• Solar Expert Posts: 72 ✭✭
icarus wrote: »
I have had several old Servels over the years (Still do, but don't use them) including several kerosene types. I may be mistaken, but I don't think any of the 50's vintage LP fridges had an automatic adjusting flame. There is an flame adjustment, but no thermostat control for it. The trick was to get the cabinet cold, then slowly turn down the flame over a period of a few days, with a fridge thermometer as a guide, until you got to the desired temp. The problems that I routinely encountered with these units were rust and soot causing the burner to burn dirty.

I agree with you, that properly adjusted, they burn as clean as any gas range. The problem is with users who either don't know how to check them or fail to check them regularly.

I stand by my previous statement: I wouldn't allow anyone to sleep in a small building with an unvented gas fridge burning WITHOUT a C0 monitor.

Tony

PS. I don't know if the newer versions of the Servels C1960+, were any different. I think that Servel and Dometic are one company now, but it seems things keep changing. I know nothing about Whirlpool gas fridges.

Why would you change a LP fridge to Nat Gas? It seems if you have Natural Gas available you would also have grid power available, and therefore be using something more efficient than an old Servel/Whirlpool.

Servel and Whirlpool marketed their gas refrigerators to both city dwellers on natural gas and rural folks on propane. If you ever see their original ads, their emphasis was on "silent". Servel even made a model with an electric heating element that replaced the burner so you could plug it in to AC thereby eliminating gas lines. My best guess is at least 50% of all Servels were originally made for natural gas from the factory.

Kerosene refrigerators do not have minimum and maximum flame controls like the gas refrigerators did but they can be converted to propane with controls. The soot you experienced was either an improperly adjusted flame (not enough air) on propane or the use of kerosene. Servel used Aladdin lamp burners for their kerosene refrigerator burners. In the same way an Aladdin lamp will soot up a chimney if it's turned up too high, the same thing will happen with a kerosene refrigerator of any make. If the flue is clean and free of rust to begin with and the burner is properly adjusted, the flue WILL stay clean in the same way as a furnace or water heater flue stays clean and free of rust and or soot.

Maximum flame gas pressure must be set at 10.2 inches of water column and minimum flame between 0.4 and 1.7 inches water column depending on model. A properly adjusted 2,500 BTU burner will cycle down to 220 BTU at minimum flame. All Servels (excluding kerosene) from at least as early as the 1930's through the late 1950's including Whirlpool had controls that cycled between maximum and minimum flame.

Over the last 30 years I've personally converted many natural gas Servels to propane.

We used Servels for 28 years and they worked great for us and our neighbors although we now use a RF19 Sun Frost.....wife wanted a larger freezer. If we could have found one of those elusive Servel chest type freezers, we'd still be using unvented Servels......SILENT!
• Solar Expert Posts: 5,436 ✭✭✭✭
jacobs wrote: »
Servel and Whirlpool marketed their gas refrigerators to both city dwellers on natural gas and rural folks on propane. If you ever see their original ads, their emphasis was on "silent". Servel even made a model with an electric heating element that replaced the burner so you could plug it in to AC thereby eliminating gas lines. My best guess is at least 50% of all Servels were originally made for natural gas from the factory.

Kerosene refrigerators do not have minimum and maximum flame controls like the gas refrigerators did but they can be converted to propane with controls. The soot you experienced was either an improperly adjusted flame (not enough air) on propane or the use of kerosene. Servel used Aladdin lamp burners for their kerosene refrigerator burners. In the same way an Aladdin lamp will soot up a chimney if it's turned up too high, the same thing will happen with a kerosene refrigerator of any make. If the flue is clean and free of rust to begin with and the burner is properly adjusted, the flue WILL stay clean in the same way as a furnace or water heater flue stays clean and free of rust and or soot.

Maximum flame gas pressure must be set at 10.2 inches of water column and minimum flame between 0.4 and 1.7 inches water column depending on model. A properly adjusted 2,500 BTU burner will cycle down to 220 BTU at minimum flame. All Servels (excluding kerosene) from at least as early as the 1930's through the late 1950's including Whirlpool had controls that cycled between maximum and minimum flame.

Over the last 30 years I've personally converted many natural gas Servels to propane.

We used Servels for 28 years and they worked great for us and our neighbors although we now use a RF19 Sun Frost.....wife wanted a larger freezer. If we could have found one of those elusive Servel chest type freezers, we'd still be using unvented Servels......SILENT!

Jacobs,

Thanks for the information,,, just goes to show much other people know and how little I know!

Even though I lived with Servels for years, I had either forgotten, or more likely never knew that the '50's vintage would regulate their flame. Although, as I think about it now there was a thermostat bulb coming into the gas control valve, I guess I never thought about it.

I do know that the 70's or 80's dometics without electronic controls will go to low flame. Most of the newer ones have electronic controls and ignitors so that instead of going to low flame, they shut off completely. It would be interesting to know, apples to apples which type would be more efficient.

It was also interesting to learn how low the flame would go, 250btu/hour on the old guys. Mine still works, but it has been retired in favor of a modern electronic dometic. My last kerosene is used for dry storeage in my shop. The last time I lit it, it never would get cold,,I assume that it has lost it's charge. Always smelled through.

Going back to the caution about burning them in closed rooms. I still would be leery about burning a 60 year old fridge in a small, modern, tight building with out venting or a C0 monitor at the least.

Merry Christmas to all!

Tony
• Solar Expert Posts: 60 ✭✭
icarus wrote: »
Going back to the caution about burning them in closed rooms. I still would be leery about burning a 60 year old fridge in a small, modern, tight building with out venting or a C0 monitor at the least.

Given modern construction, I agree not only with venting combustion products (mostly carbon dioxide and water vapor), but also with providing a source of unheated make-up air to prevent air-starved and thus enriched mixture from increasing hydrocarbons and carbon monoxide in the exhaust, not to mention use more fuel to do the job. The CO monitor is a gotta have, IMO.
• Solar Expert Posts: 72 ✭✭
icarus wrote: »
Jacobs,

Thanks for the information,,, just goes to show much other people know and how little I know!

Even though I lived with Servels for years, I had either forgotten, or more likely never knew that the '50's vintage would regulate their flame. Although, as I think about it now there was a thermostat bulb coming into the gas control valve, I guess I never thought about it.

I do know that the 70's or 80's dometics without electronic controls will go to low flame. Most of the newer ones have electronic controls and ignitors so that instead of going to low flame, they shut off completely. It would be interesting to know, apples to apples which type would be more efficient.

It was also interesting to learn how low the flame would go, 250btu/hour on the old guys. Mine still works, but it has been retired in favor of a modern electronic dometic. My last kerosene is used for dry storeage in my shop. The last time I lit it, it never would get cold,,I assume that it has lost it's charge. Always smelled through.

Going back to the caution about burning them in closed rooms. I still would be leery about burning a 60 year old fridge in a small, modern, tight building with out venting or a C0 monitor at the least.

Merry Christmas to all!

Tony

Tony,
Don't sell yourself short. You know a lot more than I do on some subjects. I guess the only reasons I can hold my own on the old Servels are I used them, worked on a lot of them AND they don't change. I'm behind the ball on most of the new RE technology because it's always changing and I haven't tried to keep up.

If an absorption refrigerator ever develops a leak, you'll know it. You'll never forget the rotten smell. I had one spring a leak in one of our outbuildings while the overhead doors were open. Hours later I could still smell it.

My understanding is that the newer absorption refrigerators are more efficient but like previously stated they won't last near as long either. This is due to current manufacturers using much thinner walled tubing in them. It seems like everything a person does there is always a tradeoff.

You are correct about using any unvented gas appliance in a small sealed room......DON'T EVEN THINK ABOUT IT even if you have a co meter. It'll slowly reduce the oxygen level and then start producing carbon monoxide. Years ago, I was trying to adjust a Servel in a small sealed room. It would start out burning clean but a few hours later it was spewing carbon monoxide. I kept trying to readjust the burner trying different orifices and mixture adjustments but kept getting the same results. After pulling out almost all of my hair, it finally dawned on me what the problem was.....Doh! This is exactly why manufacturers install warning labels on unvented gas heaters not to install them in bathrooms or bedrooms.

One more fact I should mention, upon initial startup, an old Servel even though properly adjusted, will inevitability produce a small amount of co for about 30 minutes. Once the boiler has warmed up it will burn clean after that.

Merry Christmas
• Solar Expert Posts: 5,436 ✭✭✭✭
Moe wrote: »
Given modern construction, I agree not only with venting combustion products (mostly carbon dioxide and water vapor), but also with providing a source of unheated make-up air to prevent air-starved and thus enriched mixture from increasing hydrocarbons and carbon monoxide in the exhaust, not to mention use more fuel to do the job. The CO monitor is a gotta have, IMO.

I used to have a formula for make up air, square inches/kbtu etc. The reality is the smaller the building/room the more you have to worry about make up air. The real answer is using direct vent technology, taking outside air directly into the appliance though the burner and out the vent.

Direct venting does have its drawbacks, especially in (very) cold climates, in that they serve to cool the stack temperature of the appliance. In the case of demand water heaters it forces them to work a bit harder for example. In woodstoves it cools down the flue potentially making creosote more of a problem. On the other hand, wood stoves are big users of air, and as such they need make up air. I do a partial direct vent on my woodstove, but my house leaks enough air for the fridge, water heater and range.

I'll look when I get home for the make up air tables.

Merry Christmas to all,

Tony

PS. Jacobs, thanks for the input. I know who to write when I have questions. I do think that the new Dometics are pretty well build. Our only neighbor has one that has been burning continuously for almost 20 years. I have one that is going on ten. The biggest problem that people run into is running them out of level in RVs.

T