Rebuilt 422 Combustion & Fumes @ Shutdown

[Carl_NH]

My 422 is 12 yrs old, in 900SF garage office space with 275 external tank. Had the blower motor replaced 7 yrs ago and no other service than that.

It started shutting down last year, then this year every week or so it was shutting down so decided to have it rebuilt by Perfect Plumbing Lyman Me for $500 (kit was $300 so I felt the $200 investment wsa justified to be done by a pro who knows these units) I watched the entire process - new burner pot, ring all gaskets, cleaned and vacced the heat exchanger - lots of soot came out. Also replaced the oring on the damper assy as it was cracked, and filed down the tabs on the damper to prevent sticking. Also cleaned the small sump etc..

They checked the air flow with a manometer was low so they removed the restrictor donut and readings were acceptable (I think just under 2 on low and under 4 on high) It wasnt buring a nice blue flame so they came back again and checked the air and said this was the best they could do.. It would burn 90% blue 10% yellow on low, 75/25 blue/yellow on Med and 60/40 yellow/blue on high still not great..Also fume plumes from exhaust on shutdown.

Anyway three weeks after rebuild shut off again, restarted and it functioned until last week, -10 Mon AM, it was off again, so I tried to start and click-click - from reading here I decucted no fuel, so replaced the tank filter outside - it had 1/4" frozen gunk in base. While filter was off drained some kero - it was clear/red no water so installed the filter and bled the air out.

Now to the 422 click click a few times and alls good and running again, low, med and high, but flames still arent good. So on low I take off inlet air and play restrictor with my hand, and by reducing air its 95% blue on low! Great, so I put donut back in now 95% blue on low, with tinges of yellow at 10 and 2 oclock via the sight glass. On Med its 75% blue with yellow tips - still acceptable, on high mostly yellow with blue at the base. The damper is functioning properly as I can hear it click in/out as it cycles from high to lower.

Then on shutdown once the blower stops the exhaust fumes raw kerosene for 4-5 minutes.. not good as this is carboning up the HX I think..and also this points to solenoid pump not shutting down cutting off fuel I think maybe its dirty/got junk in it...

So today I removed solenoid pump, the bodyis blue and clean, the inlet SST filter is tan but not bad, cleaned with carb cleaner and reinstalled. Also cleaned filter on side of heater - clean too. Also checked tube feed into burner pot - clear.

Present situation with restrictor in place

1. On low burns 95% blue "acceptable" still some tinges of yellow intermittently
2. On Med 80% Blue with Yellow Tips
3. On High Yellow / some blue
4. On shutdown still fuming raw kero out of exhaust..

What do you experts say?

Bad solenoid pump, water in system? (I didnt drain the sump yet in the 422. since the filter port was clean - no water).

I dont beleive its air related as it burns cleaner slightly restricted so I am ruling out the blower motor at this point..

Thanks in advance..

Carl

[hawkins111]

M422 smell

Carl,

You did not mention any work with the exhaust flue pipe. If there was a gross amount of soot in the heat exchanger there may be a lot in the flue pipe on the exhaust side. There is even a possibility the flue pipe has a hole in the exhaust pipe. This can cause exhaust into the air side and soot up the stove. A 13 year old Monitor flue pipe is something to look at.
Any soot remaining in the heat exchanger; even after vacuuming, can cause a smell. The combustion products passing over the heat exchanger will collect the soot smell. Some Monitors can have a pretty good odor but still run fine. You should be sure to use the Air Damper in the air hose. It is all part of the system. Adjusting the air by removing the damper is a stop gap measure and won’t last long. There should be a small one screwed to the black blower case as well. The only time you remove any of the dampers is if you use an extension kit to raise the flue pipe out of the snow level. I don’t think you have any fuel pump problem. If the flame goes out within 30 seconds or so the pump is shutting off.

Tom

[Carl_NH]

Tom,

Thank you for your feedback and to clarify.

When the heat exchanger was cleaned (first in 12 yrs) there was maybe a 1/4-1/2 cup of debris was knocked out. At the same time we brushed the exhaust pipe coming out of the heat exchanger as well the double wall exhaust pipe going out side and inspected the insides as best possible. There didnt seem to be any pin holes issues with the pipe.

Regarding the mechanical damper/flapper in the blower housing the oring was split so that was replaced and checked for operation. I did not remove that damper - it is as original and functioning open/closed high/low operation.

What I did do was pull the tan air intake hose off the fresh air intake where it connects to the double wall intake manifold. Inside that is the donut air restrictor - with that donut removed (more air) and on low setting the flame is more yellow and with that donut installed the flame is 95% blue with just some tinges of yellow at 10 and 2 oclock.

I run the heater on economy plus mode setpoint 54*, and with temps from 15-20* it runs on low nonstop - no cycling which is best for these units fromn what I understad.. When the temp drops below 10 it will cycle up to med for maybe 15 minutes then down to low again to maintain the temp.

The main issue I have now is the yellow flame on high, and second is the kerosene fume plumes that comes out upon shutdown - like there is unburned fuel on the burner mat OR the soloenoid pump is leaking draining after shutdown.

Thanks again for your reply.

[hawkins111]

High flame

Carl,

If you think there is a problem with the fuel, remove the fuel line to the burner when the pot is cold. Put a cup under the outlet and try to start the stove. Fuel will come out when the status light comes on. Of course the stove won’t light, but it will run fuel through the cycle until the flame sensor tells the board to shut it off. When the lights go out watch the outlet and see if there is extra fuel. This will prove the pump problem. When the fuel is hooked back up watch the flame when the stove shuts down. There should be flame for only 30 seconds or so. If there is extra fuel the stove will show flame for a longer time.

Too much air can cause a high yellow to white flame. This can happen with a broken or misplaced gasket. It’s a hard issue to troubleshoot because you have to tear the stove back down to prove the gaskets. That’s a real pain.

I think the burner mat is installed incorrectly. Any high spots on the mat or too much glue can cause a bad flame. If it continues I would go after the mat. If you use the tube of Monitor glue, mix the whole tube up, but only use about 1/3 to ½ of the glue. If too much comes up through the weave and causes a bad flame.

Keep us posted,

Tom

[Carl_NH]

Tom,

I will do the fuel pump line disconnect test and report back - probably next weekend.

I know the fuel solenoid pump pulses so presume the stream should be moderate/pulsed fuel as well, then stop abruptly or completely and not dribble to a stop when the unit shuts off? Is there an approximate volume it should be pumping, a steady stream or?

I will also check the burner "turn off cycle" as you suggest once I do the above test.

On the burner mat, it was a complete new burner pot/mat from Monitor - here are all the parts that were replaced.

New Combustion Burner Pot Assembly
New Combustion Burner Ring
New Front Chamber gasket
New filter cartridge at tank
Flame detective plug packing
Damper o-ring
Small and Large O-ring at exhaust flue
O-gasket for ignitor
Combustion chamber gasket at Base
Heater Cover packing

As always thanks again and I will report progress next weekend latest.

Carl

[Carl_NH]

Update Sunday Feb 6

For some reason I updated this last Sunday but dont see the post.. In any event I removed the solenoid pump feed line and ran the heater.

It output for about 4 minutes a tablespoon of fuel in a pulsed low flow and when it shut off no excess fuel came out.

On shut down the burner ring glows for almost 2 minutes blue, then orange then when the fan shuts down it fumes raw keorsene out the exhaust pipe for3-4 minutes.

I am inclined to beleive its the burner mat also being out of position or now fully attached.. Thats the next thing to tackle..

Carl

[hawkins111]

422 fuel issue

Carl,

Since you used a new burner pot with mat I think the mat is fine. When there is a flame in the pot for some time after shut down, most of the time it is a blocked air or exhaust problem. The 422 fuel control is on the main board and very seldom if ever out of spec.. You mentioned a number of things you replaced on the service, but I didn’t see any mention of a burner insulating pad. If you removed the old one off the old pot and installed it on the new one that’s OK. If not, you need to get one on the bottom of the pot. You also mentioned the heat exchanger was cleaned. On an older 422 I would have removed the heat exchanger from the combustion chamber as well as the outlet adapter from the bottom of the exchanger. This allows you to dig out the bottom of the exchanger as well as shake out all the junk inside. It seems to me the air or exhaust is blocked. Long shot, be sure the stove is level. Back to front, side to side.

Keep us posted,

Tom

[Carl_NH]

Kerosene Issue - High Specific Gravity?

Hi Tom

Well I ordered and received a new solenoid pump and installed it today. Things are the same - no change.

Also got a kerosene hydrometer as I am leaning towards a fuel issue. Well I sampled in the tank today and the measrement is "heavy"

Kerosene is supposed to be .78 to .81 specific gravity, but mine is .84 range so. I got the last 150 gal delivery about a year ago and thats when things started to go downhill..

Doing some reading the temp corrected reading (to 60* F) would add .01 - each 3 degrees below 60 add .001 is what I understand, so if I add this to it I am still at .83 outside the speced tolerance..

My thinking is it might be partially contaminated with Fuel Oil.. as that is denser than kerosene..

What are your thoughts on this? Since right now its buring OK on low and med low, but on Med and high yellow flame still.

Thanks

Carl

[hawkins111]

fuel too heavy

Carl,

If you have an idea you got the wrong fuel and it measured high, you have a big problem. You can take a sample of the fuel in a clean glass jar. If it is clear and bright you have #1. If it is straw colored you have # 2. Monitors are not meant to run on #2. The longer you run it the worse it will get. You need to remove all the fuel and get the right stuff. Change the filter and hope the carbon build up is not bad enough to cause trouble. Don’t try the additives as they will not work to reduce the amount of carbon in the fuel. Bite the bullet and change the fuel out.

Good luck,

Tom

[Carl_NH]

Tom,

Its red colored fuel, not yellow, or amber. My next step is to get a fresh sample locally and test my hydrometer against to verify the reading - I am doing that today (Sunday).

If the sample falls in the "good" range of .78-.81 SG the next call is the Fuel company Monday morning. Its the same supplier for the last 12 years, to "discuss" their last delivery as it was after that the unit began shutting down, and if never occured to me they might have bad fuel or mixed with # 2 Fuel oil.

Dont get me wrong - the unit is running decent on low, its on Med and High we have the yellow flame, so its not sooting up in over 150 hrs running - but this is something I want to get to the bottom of - I want it running properly.

Carl

[Carl_NH]

Fuel Tests & Update

Well, called fuel co, (been gettnig kero from them for 10 yrs) and last delivery was June 2010 150 gal. which is hydrometer testing at .84 - way out of range.

So today picked up a fresh gallon of K1 and checked the density - its .79 - a perfect/good reading for Kero so my hydrometer is right on. So pulled front covers off, shut off fuel supply, pulled the pump then suctioned all the old fuel out of the M21 resivoir tank and filled with the fresh keorsene.

Also put my old one back in (measured 565 ohms perfect).

So turned unit on and Blue Flame, Lo-Lo Med, Med and High !! Yes.. It was fuel. so it ran for about 20 min then let it shut down. NO Fumes from exhaust either.

So I wrote a lengthy email to oil Co explaining this issue and requesting this kero be removed and fresh new kero put in.. I offered to have them fill the tank (its at half now) so we can start with a "clean slate" . Its a locally owned co and i am dealing with the owner - a lady..

Now we will see what she says on Monday as they get the kero from Sprague Energy a distribiutor in NH.. so will take it one step at a time.

I will be testing the new delivery before we fill too. Do you think this is a reasonable approach? Did I miss anything?

Thanks

[hawkins111]

#2 fuel problem

Carl,

I think you are being more than fair with your fuel company. When this happened to me in the winter of 97 my fuel company would not do anything. I ended up with 220 gallons of #2 in a separate tank. Here in Alaska it is a big deal to end up with #2, as it will not flow at 0 degrees. By ordering a full tank I would think your fuel company will fall all over themselves to fix the problem. It’s too bad NH has dyed fuel. You can tell the difference between #1 and #2 just by looking at a sample in a clean jar.

Keep us posted on the results,

Tom

[HayZee518]

I just checked an online chart for KEROSENE. At 60C specific gravity is .820. So how is .79 a "perfect gravity?"

[Carl_NH]

Specific Gravity of Kerosene

HayZee518,

Thanks for your feedback on the topic. The SG of kerosene is fairly tight - the acceptable range is from .785 to .825 with the "best" being .79 to .81. This was done yesterday @ 52*. The test specs say 60F or I believe 20C as the "mean" temp for testing purposes.

Usually under .79 and over .81 it is outside the tolerances for "good" kerosene. It is also jet fuel as you may know and they have fairly tight controls and checks on this.

I presume you've read the events leading up to this, and with my Kerosene checking/verified at .84 or even a little heavier, then with the addition of the "good" product it burns well, doesn't fume at shutdown points directly (in my opinion) that the product in my tank right now at .84 is causing the issues. Also on the fresh Kero, it was hotter..

Have you used a hydrometer and checked fuel issues before? What's your opinion as to what a Monitor should handle from a SG variance and still run well?

Thanks

[HayZee518]

I have never gone that far to measure my supplier's specific gravity. I do get dyed kero. I haven't filled up since the last days of December. I imagine I will get more before the end of this month. I been running my setpoint at 72 degrees, 24/7. So far so good, the unit hasn't even burped. It used to shutdown about every other day because of water in the fuel line. I have gotten around that by jacking up the exit end beyond horizontal so that the condensate drains back towards the other end and the outlet is in pure kero.