Quick fix for stuck Hydro Hot check valve

[MBnKen]

Quick tip....learned today from Vehicle Systems
I fired up the furnace for zone heating for the first time in a number of months. We used the diesel burner regularly for hot water when traveling but had not used the zone heat. Zone 1 worked great when fired up. Zone 2 no heat.

I pulled out the shop manual and checked the power and lights on the panel. The lights for the zone 2 - 3 were on, the little fans in the exchangers were running, and circulating pump 2 had its flywheel running as expected....but still not heat.

Called Vehicle Systems and found out that the return flow check valves right above the circulating pumps sometimes stick when the unit is stored for awhile. The fix is simple.... turn on the zone and make sure the diesel burner has completed its heating cycle. Then locate the pump's outflow check valves. They are brass and have a nut on the front and a smaller one on the side. They are inside the Hydro-Hot just below the exit points for the hot fluid. You tap them gently with something solid to loosen the valve. I had to tap a few times. You know they have opened since the hose above the valve immediately gets hot and the zone starts heating again.

[MBnKen]

Quick tip....learned today from Vehicle Systems
I fired up the furnace for zone heating for the first time in a number of months. We used the diesel burner regularly for hot water when traveling but had not used the zone heat. Zone 1 worked great when fired up. Zone 2 no heat.

I pulled out the shop manual and checked the power and lights on the panel. The lights for the zone 2 - 3 were on, the little fans in the exchangers were running, and circulating pump 2 had its flywheel running as expected....but still not heat.

Called Vehicle Systems and found out that the return flow check valves right above the circulating pumps sometimes stick when the unit is stored for awhile. The fix is simple.... turn on the zone and make sure the diesel burner has completed its heating cycle. Then locate the pump's outflow check valves. They are brass and have a nut on the front and a smaller one on the side. They are inside the Hydro-Hot just below the exit points for the hot fluid. You tap them gently with something solid to loosen the valve. I had to tap a few times. You know they have opened since the hose above the valve immediately gets hot and the zone starts heating again.

[rebelsbeach]

[TaxedtoDeath]

MBnKEN,

Thanks for the tip on the hydro hotsystem!

Because I don't leave for Florida until after Thanksgiving, I need to be aware of freezing temps and I run my hydro hot to keep my coach toasty.

In early October, I cranked up the zones (inside the coach) and was pleased to find that all was well. I also assumed (who would have thunk?) that because all was well above, that the bay heat zone was also working.

I checked today and all is OK (whew!- it was working) in the bay compartment. But you certainly have made me aware that each individual zone needs to be monitored to be sure they are circulating.

Thanks again!

[Lug_Nut]

MBnKen, Great tip! These tech tips are real handy. I haven't had any problems with mine yet, but this type of issue is probably more common than we think given the long non-use of HH that many experience.

Peter

["007"]

Its strange because the fluid in heating system feels slippery to the touch. Would think valves would always be lubed.
Its a good tip if anyone does have a problem.