| Author | Message | ||
| Matt (Hgtech)
Rating: N/A |
Does anyone have anything good or bad to say about the Coleman HP2 roof units? http://www.rvcomfort.com/pdf_documents/hp2heatpump.pdf We've got a single 13,500 Carrier AirV right now that i'm not too impressed with. Isn't too bad for cooling but the heat strip function is useless. It also looks like the Coleman is quite a bit smaller in exterior size than the Carrier we've got now. Also the Coleman is 15,000 of AC and 12,700 of Heat. We would do at least three of them which would give us 45,000 of AC and 38,100 of Heat. If you wouldn't recommend the Coleman - is there another heat pump style unit you would recommend? Thanks!! Matt 1979 Silver Eagle Model 05 | ||
| JR
Rating: N/A |
I cannot comment on the Coleman, but I have two Dometic heat pumps installed and they work great. One thing to keep in mind with heat pumps is that below about 40* the heat function becomes less than desirable. Above 40* they will produce plenty of heat. You'll have to install some sort of backup heat...LP or electric, if you plan to use your coach in really cold weather. I've got an RV style Hydroflame 31K backup forced air furnace. LP allows some drycamping, but, most heating systems are pretty rough on batteries. LP is the least battery hungry. Catalytics are not battery dependent. Regarding electric heat, I've heard of some campgrounds charging usary fees for electric heaters. May meter the pole. I once had a Coleman with heat strips...IMHO the heat strip was worse than useless. Wife's hair dryer made more heat. My dos centavos, JR | ||
| truthhunter@shaw.ca Rating: N/A |
The heat claim of 2.5 times heat from the heat pump over using a regular electric heat is presumably taken with a outdoor ambient (slightly cool out) temperature of 47 F degrees {placed on the floor? or at the ceiling?) makes me curious as to what the efficiency rating and effectiveness would drop to for the heat pump when the outdoor temperature was closer to 32 F. I have no experience with heat air to air heat pumps as they are not cost effective way up hear. Would be useful to find more meaningful specifications on efficiency and performance should I go the carbunkcle route some day. | ||
| Nick Badame Refrigeration Co. (Dnick85)
Rating: N/A |
Matt, First, I am a DOMETIC dealer: Not to sell you but, inform you. Please review information on the Dometic Penguin 15,000 & 13,500 Rooftops. they come in H.P. and standard A/C. They are noted for their Quiet operation And multipal fan speeds. But most of all, Their LOW PROFILE. http://www.dometicusa.com/climate.php?product=52 Good Luck- Nick- | ||
| David (Davidinwilmnc)
Rating: N/A |
I have a Carrier 15K heat pump. Here in southeastern NC, it works very well most of the year. It will keep this conversion in progress (meaning not much insulation) warm down to the upper 30's. There's a switch on the outdoor coils that switch off the compressor and switch on the strips at this point. If the bus is already warm (about 67 or higher) inside, the strip heater will keep it above 65 when the temps drop below freezing. I'll also have an LP heater for backup like JR. If you're installing roof A/C's, I think it would be a mistake not to use heat pumps. Mine was $675 shipped. | ||
| Geoff (Geoff)
Rating: N/A |
I have two of the Coleman HP2 units on my RTS, along with one 15,000 Coleman AC. Unless they have changed their design, I would not recommend the HP2's. I have a lot of problems getting the heat pumps to work, and I have determined that the problem is in the design of the tubing that allows the reverse flow of freon for the heat pump function. I complained to Coleman about the poor heat pump flow and they told me they had never had anyone else complain of the problem, which is unlikely since I have two of them and they both act the same way. Anyway, what I have to do to get the heat pumps to start working is to turn the heat cycle on and off several times until the freon starts flowing good enough to get heat. I added a timer delay to the reversing valve and that has helped the reverse flow but has not cured the problem. Buy a different brand of heat pump! --Geoff '82 RTS AZ | ||
| Larry Baird (Airhog)
Rating: N/A |
You guys just need more, like mine. http://www.ljbphotography.com/bus.htm Larry | ||
| David Hartley (Drdave)
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Larry, What were you thinking? You gotta be a desert dweller with that many a/c units.....  | ||
| John MC9 Rating: N/A |
I've seen what FF calls "carbuncles", but this is truly the first bunch of busuncles I've seen! (someone call FF) | ||
| Matt (Hgtech)
Rating: N/A |
Drdave, I think I've figured out what Larry was doing!!! He obviously owns stock in the a/c unit company!! Larry, I'm curious - what size Genset are you using to run all those things (or do you run them all at once)? Matt 1979 Silver Eagle Model 05 | ||
| Stan Rating: N/A |
I know nothing about the Coleman RV heatpump but when using electric heating it is generally accepted that heatpumps (working properly) are cost effective down to 40 degrees F when electricity cost .10/kwh. Below 40 degrees it is cheaper to use electric heat strips. Heatpumps are being installed in houses and commecial building in Alberta that use 45 degree ground water as the heat source. The Federal Dept of Energy claims they are cost effective even in -40 F weather because the ground water stays at a constant 40 degreees. | ||
| FAST FRED Rating: N/A |
"Below 40 degrees it is cheaper to use electric heat strips." Fraid not. The heatpumps are much more efficent than the heat strips (at 40f+) and some will output a good percentage of their air cond rating 10,000 or more BTU as heat. A heat strip of 15A does not come close to that, so 2 or 3 heat strips are needed to stay warm. Heat strips are "100%" efficent BUT your power pole may melt keeping then glowing. A furnace is the way to stay warm at 0F FAST FRED . | ||
| Pat Bartlett (Muddog16)
Rating: N/A |
Jim Stewart, and Paul Elbisser, had some great information on the new Carrier Low Profile Heat Pump Units. I emailed the contact that Jim posted in the thread "Carrier low profile roof air conditioners", and they returned my email and said that this very week is the scheduled date for them to be available they are going to send me information as soon as it is available, my choice will be between the Domectic LP/HP unit and Carrier. Pat | ||
| Nick Badame Refrigeration Co. (Dnick85)
Rating: N/A |
Fred is correct, The heat strips don't produce their value in electricity to btu's! If you can't go propane, go with H.P.'s! But remember, H.P.'s only produce down to 36degs so if you plan some winter trips, have a back up!!! The Dometic Penguins produce 12,500 btus in heat, much more than other brands! Nick- | ||
| Pat Bartlett (Muddog16)
Rating: N/A |
Nick I sent you a email! Pat | ||
| Stan Rating: N/A |
Nick: Since you are in the refrigeration business you probably have access to lots of information on heatpumps. Do you have, or do you know where to get, charts that show BTUs in versus BTU's out over the heating season ambient temperature range. When I talk to dealers all they will tell me is that I will save money but they won't give me the numbers to let me work it out myself. This is for house heating and I have access to natural gas, propane and electric so it is easy to compare prices when you know the BTU ratio. | ||
| JW Smythe (Jwsmythe)
Rating: N/A |
Guys, On the 40 degree issue, here's what I remember from HVAC class years ago. Air conditioners put out 40 degrees on the cool side. The move that heat to the hot side, at whatever temp. It may have been specificed, I don't remember. When you go into heat pump mode, a valve literally switches the flow, so the function of the hot and cool side are switched. Heat pump mode is attempting to cool the outside to 40 degrees, and transfer the heat inside. It's all good, until it gets close to 40 degrees outside. The system may be running, but it won't be transfering any heat. There's no reason to design a home air conditioner or heat pump to service temperatures below 40 degrees. People will never set their air conditioning anywhere near 40 degrees. Any home heat pump will have a secondary heating method. The method will depend on your application and/or area. Places that use a lot of natural gas, you'll have a gas burner. Places that don't will have electric. The secondary heating will automatically kick in, so you may be completely unaware that it's even happened. Most thermostats have a little light on them that say "secondary" or "emergency" heat. Gawd, I've soaked up a lot of useless knowledge over the years. | ||
| Matt (Hgtech)
Rating: N/A |
Pat, They didn't happen to give you any idea what the cost of one of those units would be did they? Matt 1979 Silver Eagle Model 05 | ||
| David Hartley (Drdave)
Rating: N/A |
Uh... Here's a cute idea... Take a Central a/c unit for a house and install it in the bus. Find one that has a high seer rating and low compressor amp draw. Ok so it will be a 220 volt unit but of you can find one that needs about 15 amps @ 220 volts with the fans. then most 50 amp services and generators will handle it. My RUUD home system draws 9 amps for the outside unit and 3.5 amps for the inside unit. Then if you can find a nice step up transformer or 24 volt to 220 inverter I am sure that you could make it work. I have been thinking about one big system to replace my roof airs. Hmmm.... | ||
| JR
Rating: N/A |
As one with experience with Dometic rootop heatpumps...I can advise that you will not want to extract the last btu of heat from the unit. They will still supply some heat with temps down into the low 30s but rooftops move a lot of air, and a 68* degree discharge feels like an icemaker. Feels like an Arctic blast. Above 40* they discharge warm air. Both of my 15K cool/12.5K heat Dometics will run on either heat or cool with 30 amp service. 30 amps are used up, but you're cool! At night, only one unit is necessary...for my ooach. I run the front only once the sun sets. Another nice thing about roof airs...they have redundancy. Regarding Drdave's installation of a modified home unit idea, Christy Hicks has done that in an MCI. She posts frequently on the MCI site and has pix of her heat pumps installed inside a bay. Pretty elaborate. JR | ||
| Larry Baird (Airhog)
Rating: N/A |
I have two 7KW gensets and can run 4 with them and one on shore power. In case the refer quits I put the food on the table. I do live in the desert, Palm Springs but I like to be gone in the summer. Larry | ||
| Matt Bennett
Rating: N/A |
Um, I hate to jam my nose into something on my first posting, but I've done quite a lot of a/c work, including heat pumps and maybe I can clarify a couple of things.. first the gentleman who said that a/c units put out 40 degrees on the cool side is not entirely correct. the evaporator temperature (aka output air) is directly correspondent to the temperature of the air passing over it. a/c techs talk about something called delta T, which is difference in air temperature over the evaporator coils. 40 degrees is about the coldest I'd like to see suction temps, because any lower and the coil is too close to freezing up. I've seen guys run them down lower, but a little dirt and they go frosty if the thermostat is down too low. This is also why the hp is nearly useless near 36 or so outside temp, because the unit is also dependent on outside air temperature, in terms of pressure/temperature. So once the oustside air is really cold, the pressure drops way low in the system and that means colder outbound air. Technically its working, but like the other guy said, 68 degrees in the winter is small comfort. Heat pumps are highly efficient in moderate temperatures, but really cold winters make them worthless. I sold a lot of them in GA, but if you are going to spend substantial time in subfreezing, you might be better off just buying standard a/c units and putting the savings into conventional heat. With heat pumps you'll either have blistering power usage or really lousy air quality (perceived heating). Wow this is long. Sorry. |