Alde: HW works, but not heating

DurangoTaB

I don’t think I’ve seen this one on this forum before (and certainly not personally).  We had the pleasure of going camping for 2 nights in Utah earlier this week.  Fortunately the nights only got down to the mid 30’s because, for the first time, the heater didn’t work.  HW heated up fine, but when I switched to HW/heat and turned the thermostat up, it’d fire up for about 30 seconds then shut down and turn the red light on.  I was pretty sure I heard the pump circulating.  I’ve blamed swapping out propane in the past (which I’d done for this trip), but the Alde was working fine for HW (although that took quite a few resets).  I checked all fuses (and yes Jenn, the exhaust hose!)...all good.  Checked the glycol...about 1/2” above minimum.  Anybody have a hunch?  Clogged pump?  Hmmm...

Sharon_is_SAM

Does your Alde have the automatic air bleeder?

DurangoTaB

Good question...we got it in the spring of 2014, but it has almost all the (then) new features of 2015 (LED lights, screen door, etc.).  I’ll check the literature than came with it...

Spruce1

Does it work on shore power? The Alde in our 2014 MaxS would run for at most 2 hours (sometimes much less, like 30 seconds) then the steady red light.  In the couple hours it ran the water would get hot.

Both hot water and heat worked fine on shore power.  

I swapped LP tanks, topped off the glycol, verified that the pump was working, checked the fuses (all good), and reset the Alde numerous times by disconnecting the 12v at the battery. All to no avail.

Eventually I brought it to the dealer and they determined it was low pressure at LP regulator.  The dealer tested the system after replacing the regulator and reported it worked fine. I personally didn't get to test it though because it went directly into storage.

Hope this helps!

DurangoTaB

@Spruce1... Verrrry interesting...as this is only the second time we’ve gone camping since I installed the “high altitude” secondary LP regulator (drops the pressure from 11” to 8” ahead of the Alde (the stove and fridge stay at 11” WC).  I don’t think we needed the heat on last time, so this is the first time for HW + heat.  Odd that it fires up OK for hot water...but not for heating.  
@SAM... the manual (mod. 3010) talks about bleeding...but doesn’t say how.  I don’t see any automatic valves, or manual for that matter.  I also don’t see any valves or low point drains for the glycol...looks like a messy job to replace it (recommended every 2-3 years).

Sharon_is_SAM

Wonder if anybody else with the high altitude fix has encounter problems.  We are scheduled for the mod at the end of the month.

ScottG

@DurangoTaB, this seems peculiar. The hot water and the cabin heat are provided by the same propane burner, so I'm at a loss why one setting would cause a propane blockage or overheat condition (indicated by a solid red light) while the other did not.

However, the Alde does heat to different temperatures depending on whether you select heat/HW or just HW, suggesting that different control circuitry is activated by these different settings. Therefore, I might suspect a faulty internal temperature sensor. According to the manual, this condition would also trigger a solid red light:

From page 17...

G. Red LED flashes if the voltage to the boiler goes below
10,5 V (automatic resetting at higher voltage). Fixed light,
the LPG boiler has become blocked (resetting by the central
switch for LPG) or overheated (resetting by the main
switch of the vehicle). The temperature sensors of the
boiler could be defective as well (resetting not possible).

DurangoTaB

@ScottG...I saw that too...but our voltage never dropped below 12.2V all day/night.  And I’m equally confused why HW would work and not heat!

DurangoTaB

@SAM...we live at about 7000ft, and were camping at 6500ft in Utah, so I don’t think it’s the elevation (and NuCamp claims the reduced LP pressure works fine at all elevations.

jkjenn

SAM said:

Wonder if anybody else with the high altitude fix has encounter problems.  We are scheduled for the mod at the end of the month.

I am thinking about doing that this spring. Are you doing it at the deal or the factory?

Sharon_is_SAM

Jkjenn, we are having it done at the factory.

ScottG

DurangoTaB said:

@ScottG...I saw that too...but our voltage never dropped below 12.2V all day/night.  And I’m equally confused why HW would work and not heat!

@DurangoTaB, I was referring specifically to the last sentence in the paragraph from the manual, not the first.

I interpreted your initial post as the red light being solid as opposed to blinking. That could indicate (among other things) a defective temperature sensor.

Since the "heat" setting and the "heat and hot water" setting involve different temperature controls, that could explain why the problem surfaces on one setting but not the other.

DurangoTaB

@ScottG... Sorry for the confusion, but you could be right, and it was a solid red light. I’ll check with NuCamp & Alde tomorrow on how to troubleshoot the temp sensors (the nearest Alde/T@B dealer is 200 miles away).

ScottG

Good luck, @DurangoTaB. Be sure to let us know what you find. That little paragraph I copied is the extent of what the users manual offers.

DurangoTaB

Got response from Scott H...will work with Marvin next week

ChanW

@DurangoTaB, on ours, the manual air bleeder is in the rubber hose in the back passenger-side corner of the Tab, under the back shelf. 
The auto bleeder is in the Alde compartment in the top-most rubber hose a few inches from the Alde. It's a brass cylinder looking thing, and has a clear vinyl ¼" tube coming off of it that goes through the floor to drain any liquid.
The glycol drain is in the Alde compartment on the lower hose, with a tee fitting that goes through the floor. On the bottom of the Tab, it looks like a 1" black hose with a brass plug in it, with a hose clamp holding it in.
If you need pics, I will post some.
Just for your reference.

DurangoTaB

@ChanW...thanks!  Is this brass “made in Italy” thing the auto bleed?  Since your T@B is about the same age as ours, have you drained & replaced your glycol?  Thanks again...most helpful.

DurangoTaB

More data points...I pulled the T@B onto a flat area by our drive, and tried the heater (no water in the lines...winterized for some cold nights here).  After 5 tries and red light resets the Alde fires up, continued firing for 5 minutes, all the while the circ pump goes on & off every 10 seconds...the it shuts down & solid red light.  I did this 3 times with the same results...

Verna

@DurangoTaB, I had Austin change my glycol last summer. I‘ve had it for two winters and since it’s so important for my snowbirding comfort, I don’t mind having him change the glycol every two years. 2014 exterior, 2015 interior with 2016 upgrades. 

ChanW

@DurangoTaB, yes, that's the automatic air separator.

These air separators are common in hydronic systems (there are a number of them on our home radiant system). But I'm thinking that they aren't really for bleeding large quantities of air, like you would have after draining and refilling the glycol. They're more intended to bleed the small quantity of air that separates from the water (glycol) as it's heated.

The manual one in the back corner is more likely to be used to remove air after draining and refilling the glycol. 

Yes, I changed ours this fall. It was tedious and time consuming, but not difficult. Discussed here: http://tab-rv.vanillaforums.com/discussion/2360/anyone-attempted-a-glycol-exchange-on-alde

ChanW

I wonder if there's something tangled in your pump, restricting it. Did some kind of debris get into your expansion tank somehow? 

DurangoTaB said:

More data points...I pulled the T@B onto a flat area by our drive, and tried the heater (no water in the lines...winterized for some cold nights here).  After 5 tries and red light resets the Alde fires up, continued firing for 5 minutes, all the while the circ pump goes on & off every 10 seconds...the it shuts down & solid red light.  I did this 3 times with the same results...

DurangoTaB

Thanks...good suggestions...if the weather warms up a bit I'll try draining & refilling the glycol.  Not sure how anything could've gotten into that closed system though...

jkjenn

DurangoTaB said:

Thanks...good suggestions...if the weather warms up a bit I'll try draining & refilling the glycol.  Not sure how anything could've gotten into that closed system though...

Red light (per the manual, I believe) indicates an LP blockage. Have you checked the exhaust hose and to make sure the vent is free of critters?

DurangoTaB

Hmmm...I checked the tightness of the clamps, but it’d be worth a shot to check inside!

DurangoTaB

I haven’t received the glycol from Elsie yet and haven’t heard from Alde U.S. (Spencer?), however I did reach out to Alde U.K. (lots of Alde dialog there) and bless their hearts, got a response right back...fyi:

Hello sir,

Greetings from a very rainy Wellingborough, Northamptonshire, UK!

On propane heating, the big difference in behaviours is: On hot water boost (ramp full volume), the system will only use gas stage 1 (11K BTU, fan @half rpm). For normal heating, the system will use gas stage 2 (18.7K BTU, fan @full rpm).

So scenarios are, that the gas valve is failing at stage 2, or fan is failing at stage 2, or if there is a restriction in the pipes, the extra power from stage 2 might be causing an overheat.

There should be an error message displayed on the Standby Screen of your Alde control panel, between two yellow triangles. This will narrow down the fault for your service agent.

It's a busy time for the Alde North America team at present, with the National RV Show in Louisville.

https://www.alde.us/events/

But we've referred you to them, and we're confident they'll be in contact with you very soon.
info@alde.us

Best regards,
Joakim Johansson
Customer Service Advisor
Alde UK Team

Om3

Hi Durango!!! We experienced a similar issue with our T@B 400...the het did not work! Because there are not any trained T@B400 dealers in the NE we traveled to Sugarcreek to get the system
working! We left our T@B for the day with Marvin at NuCamp who oversaw the work that needed
attention. At the end of the day...there was air in the line!!!!! Before leaving, Marvin made certain
that the heat would circulate and heat up the cabin. Despite a long long ride in pouring rain....
coming and going...we have heat!

DurangoTaB

@Om3... sadly Sugarcreek is a bit of a drive from Durango!  Since most T@Bs have an automatic air bleed I’m wondering how it got in there, and how to bleed correctly when I change out the glycol.  Thanks for the info!

Om3

Sure is Durango...long ride from MA...but, not as long as a journey for you! Not sure wither...but, it works now!