Community Forums

mssimpson · 01-14-2025, 07:31 PM

Greetings! Been watching and learning from you all for months since buying my new-to-me 2021 Tiffin Phaeton 40IH. My first post, so.....here goes. Furnace in front of coach started blowing cold air. Rear still blowing hot. Not running hot water, so no conflict there. I suspect maybe dirty filter? anyone know where the furnace filter is?

thanks

2021 Tiffin Phaeton 40IH
2024 F-150 toad
Roadmaster Nighhawk/invisi brake

Old-Biscuit · 01-14-2025, 08:05 PM

Unusual for an RV Furnace to have a filter

Rv furnace blowing cold air means it is not igniting the propane

Could be circuit board issue
Could be Spark Electrode issue
Could be propane issue

Brand/Model of furnace??

SamKVA · 01-14-2025, 08:10 PM

Welcome and congrats on your 21 IH! You will love the floor plan. However, a lot more details of your coach would be helpful. Especially, to know if you have propane furnaces or the AquaHot system.

Thanks!
Sam

Shawn Cole · 01-15-2025, 06:21 AM

Quote:

Originally Posted by mssimpson

Greetings! Been watching and learning from you all for months since buying my new-to-me 2021 Tiffin Phaeton 40IH. My first post, so.....here goes. Furnace in front of coach started blowing cold air. Rear still blowing hot. Not running hot water, so no conflict there. I suspect maybe dirty filter? anyone know where the furnace filter is?

thanks

2021 Tiffin Phaeton 40IH
2024 F-150 toad
Roadmaster Nighhawk/invisi brake

If you would give us a call with your VIN we may be able to assist you with the heat concern in the front portion of your motorhome. As it has been mentioned, we need to determine what heat source you have (LP Furnace or Aquahot) and your VIN will determine that information.

mssimpson · 01-15-2025, 04:41 PM

Thanks all! I have an AquaHot. The furnace lights up with no issues blowing hot air in the back. The front is what blows cold air. I assume only one furnace? As suggested, I'll reach out to Tiffin for an assist.

bentjm · 01-15-2025, 06:00 PM

One furnace. Two heating circuits. You need to check the pump that circulates boiler fluid to the heat exchangers in the front of your coach.

SamKVA · 01-15-2025, 07:59 PM

Quote:

Originally Posted by mssimpson

Thanks all! I have an AquaHot. The furnace lights up with no issues blowing hot air in the back. The front is what blows cold air. I assume only one furnace? As suggested, I'll reach out to Tiffin for an assist.

Are you glided in or out? There appears to be a fairly common problem with routing of the boiler fluid lines specifically to the passenger side slide that kinks the lines when glided in and no fluid flows through any front cozy zones as they are all on the same loop. We have that problem and many others have as well. I'm hoping to get ours fixed while at the Myrtle Beach Rally in April.

Sam

Ricci · 01-15-2025, 09:08 PM

Hi - Another possible issue with the AH is that the check valve for the front loop is stuck. Tap it with a hammer (don't try to slay it) and see if that makes the valve open. It happens from time to time if the unit is not used often or if the boiler fluid is too high a concentration.

Tom

garykk · 01-16-2025, 06:39 AM

First thing to do is go to the AquaHot site and download the manual for your model furnace. It has descriptions of operation , diagrams, maintenance and troubleshooting.

**Lt Dan** · 01-16-2025, 07:54 AM

To answer your first question, there is no filter on the cozy heaters or the propane furnaces either.

36PFT · 01-16-2025, 09:15 AM

Hi Our 21 35 CP had the same problem. The hose that supplied the hot boiler fluid to the front cozy heater was kinked. It was routed over the dishwasher drain line, and needed to go under the drain line. Now works great. Stan

mssimpson · 01-16-2025, 02:55 PM

Thanks everyone. I downloaded all the AquaHot manuals. Very helpful. The heat started working in the front zone after our last move, so perhaps the check valve or pump got knocked back into position or if there was a kink in the hose, it was straightened. With the manuals, I can easily check it if it happens again. Doesn't look too hard. Always helps the have the manuals!

mssimpson · 01-18-2025, 12:44 PM

Thanks again. General consensus (including Tiffin Techs) seems to be a kink in the furnace line to the front coach area. I don't see a kink in the area of the line visible underneath, so might be hidden. Hoping I don't have to take too much stuff apart to find it.

mssimpson · 01-21-2025, 07:56 AM

An update for future reference. Turns out Ricci was the winner of the best answer. The check valve was stuck and with a little tap with a wrench, flow resumed and the front furnace was back in operation just in time for the winter storm that hit Austin last night.