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Topic: No hot air from Bathroom and Bay heating elements (Read 567 times) previous topic - next topic

No hot air from Bathroom and Bay heating elements

I have a 2007 nimbus.  The bathroom and bay heating elements and not producing heat.  When I turn on the Atwood thermostat in the bathroom zone pump #2 starts and the pex lines from zone #2 in the bay are both hot.  Additionally turning on the thermostat and setting it for heat for the bedroom the heat works great from that register.  I felt the lines at both the bay element and the bathroom element and they are cold.  How can pump #2 be pumping and the lines to those heaters be cold.  Initially I was told those elements off of pump #2 are in series.  If so, how can one element be hot and 2 cold if the fluid flows from one to the other.  Any ideas from the group would be greatly appreciated.  I have spoken with Rudy Legett.  First thought was check valve.  Since bedroom works that is not the case.

Re: No hot air from Bathroom and Bay heating elements

Reply #1 –
Are the radiators truly in series where all of the liquid must go through each radiator?
Or are they in a series parallel configuration with most of the liquid bypassing the radiator to provide heat for radiators further down the line.  If the latter, your radiator is air bound.
1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Charlie, the Dog was broken out of jail 24 Oct 2023
N1RPN
AA1OH (H)e who must be obeyed.

Re: No hot air from Bathroom and Bay heating elements

Reply #2 –
That is the question that I am trying to get an authoritative answer to.  If it is what you think is there a procedure to purge that air?

Re: No hot air from Bathroom and Bay heating elements

Reply #3 –
"Normally" (which means older units than yours), the LR is on one circulator zone, the bath and storage bays are on another, and the bedroom on a third, so the fact that the bedroom registers have hot air would mostly be irrelevant to the behavior of the bath/bays.  It would normally be an issue with either the zone valve for the bath/bays (but there would not be heat in the coolant lines in that case).

I don't know if the 2007's changed that (for some reason I seem to recall they have a HydroHot not an AquaHot).

Are you saying that you have heat in the lines going to the blowers, and the blowers are running, but there is no heat coming out?  Are you SURE you're checking the lines to the bath/bays and not the lines to the bedroom?  Like I mention, those are normally completely separate zones.
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: No hot air from Bathroom and Bay heating elements

Reply #4 –
Quote from: Steve Vogel –
That is the question that I am trying to get an authoritative answer to.  If it is what you think is there a procedure to purge that air?

Still got your radiator key?
1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Charlie, the Dog was broken out of jail 24 Oct 2023
N1RPN
AA1OH (H)e who must be obeyed.

Re: No hot air from Bathroom and Bay heating elements

Reply #5 –
Not sure whether Nimbus plumbing is similar to U320, but in my coach I discovered, by accident, an unmarked/undocumented black metal valve in one of the passenger side pump bay area hoses leading to the register.  That valve shut off flow to the registers in the bath and in the basement, so mine is plumbed in series.  It's not a usual flow control valve you'll find in the rest of the system.  Guessing FT put it there in case of work on the lower registers?  Haven't seen one anywhere else in my coach (yet).  I'll see if I can get a picture of it today.  Woody.
2001 4010 U320 build #5865 "Bluto-d-Bus" since 09/18
2006 Honda Element ESP Toad
Full timing since 2016 in Western MT
Copilot: Sitka
1975 GMC 260 Avion: sold

Re: No hot air from Bathroom and Bay heating elements

Reply #6 –
Quote from: Pyolet –
. . . in my coach I discovered, by accident, an unmarked/undocumented black metal valve in one of the passenger side pump bay area hoses leading to the register.  . . .
Woody.

You don't say!  THAT is one of the better things about Foretravels.  And the chassis design, and the efficient use of interior space.

Everything is totally documented and presented to you in 3-ring binders except for the stuff that ain't.

I wonder if Mr. Vogel checked the fluid level?
1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Charlie, the Dog was broken out of jail 24 Oct 2023
N1RPN
AA1OH (H)e who must be obeyed.

Re: No hot air from Bathroom and Bay heating elements

Reply #7 –
Here's the valve.  It just spins and there's no way to tell what is on or off without activating zone 2 pump and feeling for heat.  My guess now is that it may have been put in as a flow control valve to keep full hot air off the plastic tanks???  Woody.

p.s. the photo is rotated unintentionally.  Left side is up.
2001 4010 U320 build #5865 "Bluto-d-Bus" since 09/18
2006 Honda Element ESP Toad
Full timing since 2016 in Western MT
Copilot: Sitka
1975 GMC 260 Avion: sold

Re: No hot air from Bathroom and Bay heating elements

Reply #8 –
In an Aqua Hot the bedroom coolant loop is independent of the loop that feeds the bathroom and the (perhaps) 2 heat exchangers in the wet bay. These heat exchangers should all be in series.  The heat exchanger fan in the bathroom is controlled by the bathroom thermostat.  The basement heat exchanger fans are controlled by the basement thermostat. Either of these thermostats can turn on the zone pump.

I have the same service valve Pyolet shows (we have the same year coach) but it would be highly unusual for that valve to be closed unless left so after some recent service.

The zone 2 pump may appear to be running but not actually pumping anything.

Rudy is probably best at troubleshooting this. 
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: No hot air from Bathroom and Bay heating elements

Reply #9 –
If that coach has a hydro hot then only has 2 zone pumps. I don't know how that works but I guess that it is supposed to.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins
 

Re: No hot air from Bathroom and Bay heating elements

Reply #10 –
Hydro Hot indeed has only 2 zone pumps.  Pump 1, front of coach, living room.  Pump 2, back of coach and basement, bathroom, bedroom, utility bay.

This assumes the builder plumbed it as most do.
Rudy Legett
2003 U320 4010 ISM 450 hp
2001 U320 4220 ISM 450 hp
1995 U320 M11 400 hp
1990 Granvilla 300 hp 3208T
Aqua Hot Service Houston and Southeast Texas