Help Choosing Propane Heater valve

RossdaBoss

Hello There! Need help finding a replacement valve for my Modine Shop heater unit. It is a standing pilot system and a picture of the sticker on the side of the unit is attached. Hoping for a direct replacement that I can just swap out. Any help is appreciated. Please let me know if there is any other specifications I should list. If anyone can provide a link to the replacement product that would be great!

Thanks

EBEBRATT-Ed

You would need the make and model of the gas valve. I looked on Modine web site but couldn't find a parts list for this older unit. You could try calling Modine or find a wholesaler in your area that sells Modine.

Other than that, you could give Supply House.com a try and see if they can help.

RossdaBoss

Thanks for the info Ed. I'll look to see if I can find a serial number listed anywhere on the valve.

mattmia2

what is wrong with the current valve?

RossdaBoss

Basically what has been happening is the heater blows itself out periodically. Sometimes heater will stay lit for 2-3 weeks sometimes 2-3 days. No real trigger or correlation can be found, seems to happen at random. It happens in dramatic fashion sometimes (blowing off the light cover about 2 ft away from the face of the unit). The valve also seems to leak a little around the pilot knob when being turned. I Had a HVAC company come look at it, he said it wasn't dirty, all the pressures were correct and the only thing he could think to do was change the valve as he thinks it's probably very old and not functioning properly. Only problem is he wants to charge me $2,000 to swap out the valve. Seems pretty rich for something that can just be swapped out and doesn't seem overly complicated. Just need to find the right part.

mattmia2

you need to check the pressure and do a combustion analysis and adjustment after you change the valve.

what was the voltage out of the thermocouple?

were any crossover tubes or ports in the burners clear and in place? was the inlet pressure steady? was something changed that overloaded the piping? is the service regulator failing? was the pilot burner the right size and in the right place?

RossdaBoss

all of the pressures were steady and the correct readings according to the HVAC service guy. Everything was operating exactly as it should be according to him. He tried multiple times over an hour and a half to try and reproduce the heater malfunction to no avail. It's random. He checked the regulator, the pilot, the pressures and cleaned everything as I have already done in the past. The pilot stays lit until what I'm assuming is excess gas blows itself out. I assume this means the thermocouple is operating properly since it stays lit.. He pretty much indicated nothing was wrong with its current operation and the valve must be periodically malfunctioning. Which is why that was his only suggested fix for the unit.

mattmia2

how would you distinguish between a problem with the regulator in the gas valve and the regulator at the service?

it could be that it is supposed to be a slow opening valve and it occasionally opens fast but delayed ignition is much more likely to be a physical issue with the burner, an issue with the position of the pilot, or an issue with draft.

HVACNUT

All those mini explosions can't be good for an old heat exchanger. $2K is a good chunk of a brand new heater.

RossdaBoss

no doubt. I do believe that is the reason the price tag is what it is. He said 4500 to install a whole new unit. I think he is unsure if the valve will fix the problem and wants me to buy a whole new unit to make it easier on him. So presenting me with a really expensive maybe or a guaranteed solution would push me to the guaranteed

Larry Weingarten

Hi, This sounds like an ignition problem which might be fixable with tweaks around the pilot assembly. I'd certainly start there.

Things I'd consider:

Cleaning burner assembly

Checking size of pilot

Checking pilot flame/ thermocouple contact

Checking thermocouple electrical connection and output

Checking placement of pilot flame re main burner

Checking thermocouple when main burner is running to see if overheated

No doubt there are other things, but this is a start. It wouldn't be much fun to replace the gas valve and still have the problem. 👹

Yours, Larry

hot_rod

There were some retrofit gas valve kits that added spark ignition, as wind, downdraft can some times cause standing pilot issues on ceiling unit heaters. Anything changed in the shop, exhaust system added that could pull a negative?

If it worked in the past, and the venting has not changed, it should be a solvable problem.

mattmia2

did someone take a good look at the heat exchanger to make sure it is intact?

the device @hot_rod refers to is an auto lighter. it is a hogh voltage supply with a probe that sits in the pilot flame. when the pilot is lit the flame rectification grounds out the supply and it just flows to ground. if the pilot goes out, the pilot stops conducting it to ground and it starts lighting.

if it the pilot goes out as soon as the main valve opens either the pressure is dropping enough for the pilot flame to shrink because there is too much load on that line or the service or possibly appliance regulator is not responding fast enough anymore. i'm not sur if the pilot is before or after the regulator in the valve, that would be a clue about where the problem could be.

the other option is that there isn't enough combustion air fir it to draft properly, something has happened to the cabinet or vent or vent hood to change the draft, there is some problem with the burner, or the hx is compromised and affecting the draft.