Monitor 30 heater won't light

[HeaterPCBRepair]

I picked up a monitor 30 heater and it turns on and I can hear the combustion fan run but it won't light. It hasn't been used in years. I read the manual but don't see a strainer to clean. I would like to get it up and running. Any tips on servicing this? It seems like it isn't getting fuel.

I used to work on M30 circuit board and they were pain in the neck. The only thing we did to the boards that didn't pump fuel is to resolder or better yet replace the black relays. Also resolder any of the connectors. That fixed 99% of the boards.

[rrob311]

I will have to check the solenoids soon. The heater has been apart in my garage all winter. I would really like to get this back together and running.

[rrob311]

I cleaned the fuel system out and nothing really looked clogged. Does anyone have a manual for this so I can check the solenoids? Or tell me how many volts they take to actuate? I have manuals for all of the other newer monitor heaters but not this one. I like the 30 better because its built like a tank compared to the newer ones.

[hawkins111]

The Med Solenoid has a resistance of 2300 ohm's, the High Solenoid is 2300 ohm's. The safety solenoid has a resistance of 1700 ohm's on both front and rear solenoids.

The Med Sol has a voltage of 105 volts DC at E/F on board. The High Sol has a voltage of 105 volts DC at H/G on the board. The safety Solenoid also has a voltage of 105 DC at D on the board.

Are you sure the air safety switch is working as it should? If the hose is blocked you get no fuel.

[rrob311]

Where is the air safety switch? I have been trying to locate a manual for this heater but I haven't found one yet.

[hawkins111]

I believe it's the A connector on the main board.

[rrob311]

OK, I am testing the unit now and when its on the front solenoid clicks on, the rear one does not. They are wired together in parallel so its definitely getting power. Does it have 2 solenoids on the valve so it has a redundant backup? I would imagine they are normally closed. I'm pretty sure thats why its not getting fuel. Any ideas on a fix? Or a similar part that can be retrofitted from a different heater?

[rrob311]

I took the solenoid out and checked the resistance which was in spec. So I put it back in and it started working. So I hooked up the tank and am getting fuel to the burn chamber. I turn it on and the low and medium lights come on and the combustion blower. I can feel the ignitor getting warm but its been 30 minutes or so and I still can't see a flame. Any ideas?

[hawkins111]

There are three solenoids on a Monitor 30. Med and High are on the top of the sump. The safety solenoid is down stream a little. Any wiring problems with the blower motor and safety switch can cause the safety solenoid to remain closed. Do you have a wiring diagram? If not I'll try to get you one. Send me a notification on the forum with your email address. The forum will not take large pictures.

[rrob311]

I got the heater to light, sort of. There is a little yellow flame near where the nozzle goes in when I blow on the hose going into the sump. It then dies down after I let off. Could the nozzle inside the pot be clogged? The fuel line itself looked fine when I removed it from the pot.

[hawkins111]

The nozzle could be blocked or the pot could be full of soot. What about your fueling system? Do you have good head pressure?

[rrob311]

Fixed

It looks like it is finally fixed. I took off the fuel inlet to the burn pot and cleaned out the carbon with a drill bit and a paper clip. I didn't realize it was clogged. Its cranking right now so I am happy.

[rrob311]

I am using a gravity fed 5 gallon quik tank for this.

One thing I would like to note is that the inside of this unit looks similar to my oil stove. I wonder how well it would burn #2 heating oil due to the design. The burner ring is almost the same design as the one in my oil stove.

[hawkins111]

#2 is too heavy. Too much carbon. The stove is not meant to run on #2. ULSD would work OK.