Help!! 422 Not Heating Properly

[FordMan59]

My 422 is doing something it's never done before in 22 years of service. For the last few days it's been running on high continuously. Yesterday's high was about 32* and it's currently 27*. Even running on high the indoor temperature is never getting above 69* in the house, According to Monitor if the heater is running on high the capsule tank should only last 8 hours, I filled it yesterday morning about 6:30 and filled it again last night around 8:00 and there was still probably about 1-1.5 pints of kerosene in it at the time, this makes me think it's not getting the correct amount of fuel to the burner but what would cause this? This weekend we're supposed to see lows in the single digits so I need to get this thing running right. Any suggestions of what to look for are appreciated.

[hawkins111]

What about the circulating fan and cover? Are they spotlessly clean? Then I would look at the louvers to make sure they are fully open. If you use the Economy Plus feature the stove will step down to Low and run until the temp is 12 degrees over the set temp. If set too high the unit will never get to the set temp if it is cold outside.

If the heater is running at all it is getting the right amount of fuel. Your problem is something other than fuel flow, cold house, thermistor set a too low a height, dirty fan and cover. I wish you a Happy New Years eve. Tom

[FordMan59]

Thanks for your reply Tom. I just got back home from getting some kerosene and am going to try to start checking out the heater after while. I know the fan can probably use some cleaning but there's good air flow out the front louvers. The heater has been used in this house for the last 7 winters and has never run on high continuously even in sub zero weather. The thermistor is located where it's been for the last 7 years. The current outdoor temperature is 39* the thermostat on the heater is set at 72*, it's still running on high. The temperature according to the heater is 70* and 69* according to another thermometer approximately 15' from the heater. Usually at these temperatures the heater is running on low, running less than 50% of the time and cycling on/off. My son has a 422 he's not using and said I could borrow it either later today or tomorrow if needed while I check mine out and figure out the problem.

[FordMan59]

I got the 422 from my son this afternoon. It's currently 22* outside with a forecast low tonight of 10*. This heater is acting exactly as it should and running on low. Over the next few days I plan to disassemble mine. I've already took the fan and louvers off and cleaned them, but plan to remove the fuel line spray carb cleaner through it, remove the burn chamber, inspect the flame ring, clean any sediment/soot in the pot/heat exchanger and clean all the air holes in the pot good with a torch tip cleaner. While I have it disassembled if the burn mat is questionable I'll go ahead and replace it rather than have to tear into it again in the next couple years to replace it.

[hawkins111]

Fordman, Everything is the same for the new heater, i.e. thermistor same height, Temp set at same, Economy Plus same as other heater?

[FordMan59]

Everything is the same as with the other heater. The thermistor on my son's heater had a broken wire so I just unplugged it and plugged the one off my heater into it. I wasn't using economy mode on mine nor am I on my son's. I have chronic back pain and huge swings in temperature make the pain worse. The low here this morning was about 10*. I was awake and up a few times throughout the night last night and I think the heat was running on med/low each time I was up and was when I got up this morning. It's currently 22* outside and the heater is running back and forth between low and med/low. I'll go through the heater good over the next few days and report back after giving everything a good cleaning and anything else that it may need.

[FordMan59]

Finally got around to tearing into the heater today. A few days ago I cleaned the circulation fan. Today I started out by oiling the combustion fan and cleaning it. The combustion fan was really dirty. Next I pulled the burn chamber out. The burn ring is still in pretty good condition at 6 years old next month. There was a lot of carbon build up right at the fuel nozzle, the mat was lifting and was brittle so I cleaned the pot and put a new mat in. I think my initial assessment was probably correct that there was enough fuel getting to the pot to burn a flame but not enough to put out the amount of heat it was calling for. It's all back together with the exception of putting the circulation fan back on. I'll try to take the other heater out and put this one back in in a few days. Right now they're still calling for temperatures near zero for the next few days so I'll probably wait for the temperatures to warm up some before hooking it back up for testing. I don't want to wake up some morning and it be as cold in the house as it is outside.

[FordMan59]

I know this thread is about a year old but it's still related to the initial problem. The heater was running on high all the time and wasn't keeping the temperature up in the house. I took the heater out cleaned the burn pot and put a new mat in it but never reinstalled the heater till last night because I've been using one my son wasn't using. I hooked mine back up last night and it wouldn't fire up so I took it back out and put my son's in for the night. Today I put mine back in and it finally fired up but I was getting a very low flame and after a couple minutes of running the flame went out. I took the filter out and cleaned it and tried it again, this time it didn't fire up. The pump is pumping but when I removed the fuel line there seems to be very little fuel getting to the pot. Is this likely a problem with pump or has something managed to get past the filter and blocking fuel delivery to the pot or something else all together?

[hawkins111]

The only way to trouble shoot the pump is to use your flame sensor by pass and a calibrated cup. Check the fuel flow in all three modes. Low 5.1 cc per min, high 10.3 cc per min. Check that the flow cuts out completely when it is supposed to. Tom

[FordMan59]

I've never had to do anything with the pump in mine. Can the pump be lifted out of the constant level controller with everything in place or does the tank have to come out to get enough access to remove it? If the tank has to come out how much of a problem is it to get out? I have an extra used pump that someone gave me about a year ago. If it's as easy as just removing a couple screws and pulling the pump out and putting in another one I'll try that in the next couple days. I've already been sitting in the floor a big part of the day today fooling with the heater and having chronic back pain I don't feel like spending anymore time in the floor today.

[hawkins111]

You do not need to remove the tank to get the pump out, however you will need a bent screw driver to get the two screws out. I don't think there is anything wrong with the pump. Try to clean out the nozzle port into the burner.

[FordMan59]

The nozzle at the pot is clean. I removed the pot, cleaned it and put in a new burn mat last winter when the problem started. I've also taken the fuel line off and I can blow through it and feel air at the other end so I know it's not stopped up. The pump is the only other thing I can think of that could possibly be the problem, of course I'm not a Monitor technician so I could be wrong. If you have other ideas I'm interested in hearing them. I'd like to get this heater going so I could either put it back in service or at least have it working in case something happened to the one I have been using. The igniter is working so I know that's not the problem. All the gaskets related to the pot/heat exchanger that were disturbed were replaced. If you don't think this is a pump problem do you think it could be something going on with the circuit board? I've got some 90* screwdrivers somewhere but will have to locate them. I haven't used them for anything is so many years I don't even know which tool box their in now.

[hawkins111]

In my 15 years of fixing Monitor heaters I have never seen an out of spec pump on a 422 or 441. That being said, the pump could be bad. I have seen a couple of pumps that had burned wiring. Since the pump controller on a 422 is on the main circuit board it is a rather delicate operation to mess with. I have never attempted to adjust a Monitor fuel pump and don't recommend that approach. First of all you need to calibrate the pump. If you find the pump is out of spec., it could be the pump or the main board. The only way to end that dilemma is to change one or the other with a known good part. Kind of a PITA but that's what it takes. Monitor PC Repair can fix your board if that is the problem.

[FordMan59]

Thanks Tom. I've got both an extra pump and motherboard so I should be able to figure this out with a little work/time with no additional expense. Both of those parts are used. The pump was given to me and the motherboard was bought a few months ago off of eBay. When I get the chance to work on it and figure out what the problem is I'll report it here.

[FordMan59]

I haven't tested it yet but I think I found out what was wrong. I pulled the pump out of the constant level control valve and when I turned it upside down the filter on the bottom of the pump was full of sludge/dirt and probably wasn't letting enough fuel get to the pot to fire up and burn. I cleaned it the best I could with a paper towel, soaked it in vinegar for a couple hours and reinstalled it. I also took an eye dropper and sucked the fuel out of the constant control valve to be sure there was no water/trash in it. Guess I can't complain, it took 22 years of use and probably 2-3K gallons of fuel to get enough trash by the other filters to clog the filter on the bottom of the pump.