Prescott EXL troubleshooting help needed

[19trax95]

Hello, new here to the forum as a member. Been browsing as a guest for the past few weeks.

I am having one heck of a time getting my pellet stove to run right. Little back story, we bought a house up here in northern Maine in the spring. Moved up in May. House came with a 2004 model year St Croix Prescott EXL. I tried to get it going on some of the cooler days but it didn’t want to feed pellets.

I have since been chipping away at it but I’m at nearly my end of what I can try. So far, I have replaced the vacuum switch, which didn’t fix anything since it would error out due to not seeing a vacuum on startup. I replaced all the door seals thinking maybe it was not allowing a good enough seal. That didn’t change anything. If I temporarily jump the vacuum switch, it will feed pellets and light.

Then it would error out due to not seeing the proof of flame switch close. Thought ok, maybe the switch is bad. It’s the snap switch that’s mounted to the exhaust blower housing. I tested the switch and it works as it should when off the unit and warmed to around 110-120° it’ll snap closed. I tested it both audible and with my meter. But I already had a new switch so I put the new one back on anyway. Still no change.

I’m using brand new, dry pellets, but I’m getting a lot of soot build up on the glass when I do finally get it to ignite and run. The snap switch will eventually close after I let it go through start up twice. The pellets I’m using are dougless fir, the golden fire ones from Lowe’s since the tractor supply ones sit outside. If I get this going I’m going to buy a couple tons from a local mill.

But then today, I noticed that the combustion air inlet pipe has a very weak suction to it. I can just barely feel any air being pulled in when I put my hand near it. I’m talking just enough to feel and that’s it. So I cracked the door open a little and the flame immediately got bigger and stronger. With the door closed the pellets will pile up up real bad and spill off into the ash pan before they burn. This paired with the very dirty combustion makes me say lack of oxygen. My exhaust is a horizontal exit and is about 4’ long in total. Has one 45° elbow at the back of the stove and the rest is straight through the wall.

What can I test or do next to get this thing working? Pull the exhaust blower? I have cleaned everything the best I could without tearing the whole thing down. I have read up on the leaf blower trick, but I don’t have an easy way of getting the stove outside.

 

[johneh]

But then today, I noticed that the combustion air inlet pipe has a very weak suction to it. I can just barely feel any air being pulled in when I put my hand near it. I’m talking just enough to feel and that’s it. So I cracked the door open a little and the flame immediately got bigger and stronger. With the door closed the pellets will pile up up real bad and spill off into the ash pan before they burn

From your description, you found the problem. The stove is starving for combustion air . Put in either an OAK or open a window slightly.
OAK stands for outside air kit
Welcome to the forum

 

[19trax95]

Took some time this morning and pulled the exhaust blower out. To say I think I found the problem, is an understatement. I am working on getting it all scraped clean and vacuumed out. The blower motor and fins are fine after cleaning them. Hard to see great from the pics but the opening where the exhaust was trying to flow through was about 3/4”, maybe 1”. The rest was all packed with the black creosote and debris. So no wonder why I didn’t get hardly any air flow through the stove.

 

[stovelark]

I can assure you that stove is clogged up thick with ash, St Croix's are good heaters, but are difficult to really clean out. Yes the exhaust blower and housing need thorough cleaning, as does the convection blower. The self cleaning motor and linkage needs to be cleaned too and put back in properly. But the hardest part is the ash cleanouts in the back. After you take out the internal brick (most were metal frick frames), there are cleanout doors that you need to get a brush or a wire coat rack cleaner up and in to the top, tap on the back of the stove with a hammer and watch it rain dust... The tubes in the top are probably cruddy too, but airflow is definitely your issue. When cleaned up and a little TLC, you'll have a nice heater. Good news is you're on the right track. Oh yeah, keep the wiring straight- I used to put numbers on connectors that went together, easy to get one criss-crossed, and you know how I know this!

 

[19trax95]

So those two passages on the lower right and left sides in the fire box I did get clean. I took the little doors off and vacuumed them real good, took the baffle off the top and cleaned that as well as the heat exchanger tubes. The tubes were pretty dirty but those two passages were all but full from what I could tell. I took a wire hanger and bent it up and stuck it in a drill and worked it around through those passages in the fire box as well as through the exhaust fan housing.

I got the stove running now and it is a million times better. I am working on getting the damper set properly now since wide open was way too much. The pellets were burning down out of the burn pot almost faster than the stove was feeding them. Right now I have it running on setting 3 and the damper is about a 1/4” gap and it seems to be happy. Going to continue to monitor it and see how it does.

 

[stovelark]

Sounds like you did ok with her- I usually tap on back of stove too, and the crap rains down- the convection blower down below is a bear too on those stoves, gets worse as we get older too... for the damper, the best way to set is with a manometer, if not then, when you get two horns just forming on the flame pattern, thats where I left them. Did you clean and lube the agitator rod/cam? If not, it usually will squeak and make noise around mid-season, always when it is least convenient. Glad you got her going.

 

[19trax95]

I did clean that tube as well as cleaned and lubed the cam lobe for the versa grate. I think I got the damper set pretty good for heat setting 3. Went through its first full 40lb bag of pellets yesterday without issue. It cranks out some good heat.

The glass stayed perfectly clean, flame was nice and consistent and heat output was great. So I think I finally got it. I wish I would have pulled that exhaust blower first. But in either case, it’s working perfectly now. I do have a manometer but it’s back in my storage unit in PA. Will be going back down at the end of the month to get that stuff.