Replacing Dometic Heatpump

[lass]

OK from your previous post, you bought the Penguin II ???? HP unit. Send me a PM with you email address and I can send the installation manual for the Blizzard NXT. the wiring was the same when we replaced the Penguins with the Blizzard. I'd post it but IRV doesn't accept the file size.

After the power connections, the remaining wire will just sit in the return vent

Did you get this gasket from Newmar. It is required in order to separate the supply and return vents.

[LewTippett]

Originally Posted by lass

OK from your previous post, you bought the Penguin II ???? HP unit. Send me a PM with you email address and I can send the installation manual for the Blizzard NXT. the wiring was the same when we replaced the Penguins with the Blizzard. I'd post it but IRV doesn't accept the file size.

After the power connections, the remaining wire will just sit in the return vent

Did you get this gasket from Newmar. It is required in order to separate the supply and return vents. Attachment 163118

First, yes, I have the gaskets from Newmar already installed. I also was able to get the installation guide from Dometic. However, it does not give me a compete diagram or other instructions for the wiring. I understand that there is one 12V wire, set of 3 for power, and one wire with RJ11 plug. that is all that is documented in the guide. I have two more wires on the front coming up from the hole that need a connection. I also have one RJ11 on the rear with two RJ11 plugs on the heat pump unit. Not sure which it goes in.

[LewTippett]

The one wire that i am yet to figure out for certain on both units is a small 24 gauge pair coming from the coach that I think may be the temperature sensor. I am going to wire it that way and see.

The dometic guide says that there should be two RJ11 plugs at each unit, but there was only one coming from the coach and plugged into the old rear unit. Two up front. I will go ahead and see if it works with just the one.

Still cannot see anything to do with the metal gang box connection for the power wires except to let it stay unsecured in the return air duct with the other wires. There is no cover for it either which seems to defeat the purpose of a junction type box in the first place. guess i will let it flop and see if it creates a new rattle.

[426smartin]

On my 2004 DSDP the front A/C it has 2 RJ11 ---1 from t-stat --1 goes to the rear unit. I think it does not matter which one on either unit you use. Front has the 12volts from DC supply that will supply both thru the RJ11. it also has the 2 wires for lp furnace .Hope this helps -------someone correct this if is not right.

[LewTippett]

Originally Posted by 426smartin

On my 2004 DSDP the front A/C it has 2 RJ11 ---1 from t-stat --1 goes to the rear unit. I think it does not matter which one on either unit you use. Front has the 12volts from DC supply that will supply both thru the RJ11. it also has the 2 wires for lp furnace .Hope this helps -------someone correct this if is not right.

I don't have a furnace (at least it is not listed on any of the manuals or brochure specs) and it dawned on me last night that the control cables were just daisy chained front to back. The documentation does not indicate that, but it must be. Hooking it all up this AM. Will post back status.

[bruceisla]

Originally Posted by LewTippett

I don't have a furnace (at least it is not listed on any of the manuals or brochure specs) and it dawned on me last night that the control cables were just daisy chained front to back. The documentation does not indicate that, but it must be. Hooking it all up this AM. Will post back status.

You may have more complications than anticipated.

Pleae tell us the P/N and model of your new units. This will determine what changes are needed. Also tell us what the model of the original units ... I assume DuoTherm's but please verify.

Also, what is your heating system? Propane furnace, HydroHot, heat pumps, or a combination of those.

Typically, the front unit will have (at the roof) 120vac in a workbox, a pair of wires carrying 12vdc and ground, a pair of thin wires that go to your wall temperature sensor (if you have one), and a telco style cable that goes to your thermostat, and a 2nd telco that goes to the rear A/C. The 1st telco carries 12vdc (from the top unit control board) back to the thermostat and also carries the control signals to/from the thermostat. The 2nd telco carries the signal from the thermostat (daisy from the front unit) and also carries the 12vdc from front unit to rear unit. Typically, there is no discrete 12vdc wires at the back unit. This is not a very reliable way to supply the 12vdc to the back unit and you may want to run a 16 gauge (or better) pair from the front unit to the back unit (thru the ceiling duct) that ties the 12vdc pair in the front to the rear. You will also have some other wires .... a cable to the freeze detector and another cable that is secured to the unit frame near the control board (this is the ambient temp sensor).

You should also completely replace all of the metallic tape in the plenum/duct directly below the A/C unit.

[LewTippett]

Thanks, bruceisla. I did replace the tape around the plenum in both openings. Thanks for the wiring walk through as well! I had figured it out through a bit of research and my trusty meter. Good to have someone verify it though.

I talked to Dometic and another RV tech and the problem appears to be a bad controller board in the front unit. However, Dometic says that must be diagnosed by a Dometic certified tech so I have left our coach with a local Rv Center to hopefully have it repaired under warranty. One shop told me that there is no warranty since I installed it, but Dometic did not indicate that when I talked with their customer service.

[bruceisla]

Originally Posted by LewTippett

Thanks, bruceisla. I did replace the tape around the plenum in both openings. Thanks for the wiring walk through as well! I had figured it out through a bit of research and my trusty meter. Good to have someone verify it though.

I talked to Dometic and another RV tech and the problem appears to be a bad controller board in the front unit. However, Dometic says that must be diagnosed by a Dometic certified tech so I have left our coach with a local Rv Center to hopefully have it repaired under warranty. One shop told me that there is no warranty since I installed it, but Dometic did not indicate that when I talked with their customer service.

Warranty is only affected if the failure is a result of incorrect installation.

[LewTippett]

Originally Posted by bruceisla

Warranty is only affected if the failure is a result of incorrect installation.

I had to give up and head to the service center. I had furnace wires hooked to temp sensor wire and fried my controller board. Will have to replace the board and then unit will be fine.

I am being told by the RV Center that Dometic does not recommend the low profile penguins for Newmar coaches. They are telling me that the hot and cold will mix even with the dog leg gasket sold by Newmar. Are they right?

[GaryKD]

Hi LewTippett,
No, that is not correct. Have them explain to you exactly how the hot/cold air will mix.

[bruceisla]

Originally Posted by LewTippett

I had to give up and head to the service center. I had furnace wires hooked to temp sensor wire and fried my controller board. Will have to replace the board and then unit will be fine.

I am being told by the RV Center that Dometic does not recommend the low profile penguins for Newmar coaches. They are telling me that the hot and cold will mix even with the dog leg gasket sold by Newmar. Are they right?

Well .... unfortunately, the furnace wires carry 12vdc from the furnace.

Never heard the story about the Penguin II not sealing. However, you do need genuine Dometic seals for the unit (the square seal) to match the density of the dogleg seal. They may be thinking of the Brisk II which definitely has a different base compared to a DuoTherm.

Read this and decide whether you want to update the plenum. Page down until you get to link to the PDF describing the modification.

http://www.irv2.com/forums/f103/air-...nt-334057.html

[LewTippett]

OK, since I have the Penguin II's, I should not need a new plenum. The dog leg seal from Newmar should keep the supply and return air from mixing. Am I reading you right?

[bruceisla]

Originally Posted by LewTippett

OK, since I have the Penguin II's, I should not need a new plenum. The dog leg seal from Newmar should keep the supply and return air from mixing. Am I reading you right?

Yes, the Penguin II should fit on the existing plenum with the dogleg and dogleg gasket. You can physically verify by looking at the bottom of the Penguin II and the cold air outlet should line up with the area within the dogleg (rear driver side of ceiling hole).

[LewTippett]

Thanks bruceisla and the rest! It looked like to me that it should seal up; I just lost confidence after talking to the local service center.