Boiler blower not shutting off

[Brad001]

Hi Everyone,

I'm brand new to the forum (have done some lurking) and brand new to OWB's in general. I apologize in advance for any of my ignorance.

My wife and I recently purchased a house that already had a Hardy H3 on the premises. I was pretty excited when I found out the property had a boiler so now I'm really just trying to get a firm grasp on how everything works.

Both the construction of the house and installation of the boiler occurred at the same time in 2007. The house comprises of four heating zones (garage, basement, first floor, and second floor). The garage and basement have radiators. The first floor has baseboard. For the second floor, the boiler connects to the air handler in the attic to supply heat through the forced air vents. The garage and basement each have a digital thermostat while the first and second floor have one of the round mercury based thermostats that ties to the boiler only. There is also a separate digital thermostat on the first and second floor that operate the floors respective heat pump. Currently, in the week since the boiler has been running, I only have the valves opened that run to the basement and first floor.

The biggest question/concern I have right now is that the blower to the boiler doesn't seem to be shutting off. My first suspicion (based on my limited knowledge) is with the L6006 aquastat itself. If I take the cover of the aquastat off, I see the set point dial that is at 170. There is another dial located toward the rear of the stat that after some research appears to be the differential adjustment wheel. This is set at about 13.

If I manually start to slowly turn the set point dial down, the blower will shut off eventually. I've had it shut off at around 155 and another time it wouldn't shut off until the dial hit 140.

I thought perhaps my fire just wasn't getting hot enough to heat the water to 170 but I've had it going for almost a week now with twice a day loading so I'm not really sure if that would be the issue or not. Every time I have gone outside to load wood into the boiler, the blower has been running.

Any help and guidance would be greatly appreciated. Thanks!

 

[maple1]

So how hot is the boiler getting? Isnt there a temp gauge on it?

 

[Brad001]

So how hot is the boiler getting? Isnt there a temp gauge on it?

There's actually no temp gauge on it.

 

[brenndatomu]

The biggest question/concern I have right now is that the blower to the boiler doesn't seem to be shutting off. My first suspicion (based on my limited knowledge) is with the L6006 aquastat itself. If I take the cover of the aquastat off, I see the set point dial that is at 170. There is another dial located toward the rear of the stat that after some research appears to be the differential adjustment wheel. This is set at about 13.

If I manually start to slowly turn the set point dial down, the blower will shut off eventually. I've had it shut off at around 155 and another time it wouldn't shut off until the dial hit 140.

Based on those erratic results, I would say that aquastat is bad...you should get the same shutoff temp each time you try what you did back to back.

 

[brenndatomu]

There's actually no temp gauge on it.

I think I would want to add one then...should be fairly cheap/easy to do as long as you can get to an area with a spare pipe plug that can be removed to install a sensor...

 

[Brad001]

Based on those erratic results, I would say that aquastat is bad...you should get the same shutoff temp each time you try what you did back to back.

If I'm turning the dial down back to back, the blower does seem to shut off at the same dial set temp. When I mentioned about it shutting off when the dial was at 155 and then another at 140, that was at different times. May be a dumb question, but if I put a thermometer down in the condenser stack, will that give me an accurate water temp?

 

[E Yoder]

I never understood why Hardy didn't put a temp gauge on their units. Somehow you need to get an accurate reading on temp, preferably with the pumps running to mix it to an even temperature.
I'm not familiar enough with the unit to know where you can access the tank to measure the water temp.

 

[maple1]

Without knowing accurate boiler temps you're in the dark. I suspect it is simply not getting itself up to temp. Which there could be a few reasons for. My first suspect would be poor underground lines given how old the install is. Wet wood could be playing a part also.

 

[Brad001]

I never understood why Hardy didn't put a temp gauge on their units. Somehow you need to get an accurate reading on temp, preferably with the pumps running to mix it to an even temperature.
I'm not familiar enough with the unit to know where you can access the tank to measure the water temp.

I can access the tank from the top of the unit. I can stick a thermometer down into the water and check the temp that way but I'm just not sure if that's an accurate way to measure.

 

[Brad001]

Without knowing accurate boiler temps you're in the dark. I suspect it is simply not getting itself up to temp. Which there could be a few reasons for. My first suspect would be poor underground lines given how old the install is. Wet wood could be playing a part also.

I'm starting to think you're correct with he unit simply not getting itself up to temp. The reasoning is that because this morning when I walked outside it was unseasonably warm and the blower on the unit wasn't running. On another occasion walking outside to the unit later in the day it still wasn't running. I didn't have much wood in the fire either. Also, when turning the aquastat up and down, it seemed the blower shut off and turned on at or around the temp the dial was originally set at which makes me believe it is reading accurate.

I think it may be a matter of wet wood. When I moved into the house, there was an existing wood pile that was completely exposed to the elements. No wood shed or tarp over the wood. I'm not completely sure how seasoned the wood is either. Does that sound like a likely culprit? Another question, I would imagine the larger then difference between the boiler water set temp and the outdoor temp the more frequent the blower would run. Would that be a correct assessment?

 

[maple1]

I'm starting to think you're correct with he unit simply not getting itself up to temp. The reasoning is that because this morning when I walked outside it was unseasonably warm and the blower on the unit wasn't running. On another occasion walking outside to the unit later in the day it still wasn't running. I didn't have much wood in the fire either. Also, when turning the aquastat up and down, it seemed the blower shut off and turned on at or around the temp the dial was originally set at which makes me believe it is reading accurate.

I think it may be a matter of wet wood. When I moved into the house, there was an existing wood pile that was completely exposed to the elements. No wood shed or tarp over the wood. I'm not completely sure how seasoned the wood is either. Does that sound like a likely culprit? Another question, I would imagine the larger then difference between the boiler water set temp and the outdoor temp the more frequent the blower would run. Would that be a correct assessment?

Yes. The colder it is out, the more stand by heat loss. And the more heat your heat load will draw.

 

[E Yoder]

Measuring water temp through the top of the tank should be fairly accurate if the pump to the house is running. If not the water can stratify, and be much hotter in the top. Sometime it would be good to replace the elbow above the pump with a tee, and insert a thermometer using a dry well fitting.
I'd look for some dryer wood and see how it runs.

 

[Eureka]

This does sound like wet wood. That thing will be an inferno inside with the blower fan running and a load of dry wood on top of coals.

You need to be able to see the temps if you’re going to get to know the thing; and you need to get to know it or you will hate it.

You could get a little digital probe thermometer like an Inkbird or comparable on eBay. Some have waterproof probes that you could probably drop into the top of your Hardy vent to get a spot on reading; brewers/moonshiners do it all the time. A more permanent install would be to wrap the probe to the supply port on the back of the Hardy and insulate it. Note the difference from the direct water reading as it will be less.

That will get you miles ahead of where you are now. You can burn green wood in these things but not very well unless it’s sparingly mixed with dry.

I run mine at 170 blower on, 180 blower off.

 

[Brad001]

Measuring water temp through the top of the tank should be fairly accurate if the pump to the house is running. If not the water can stratify, and be much hotter in the top. Sometime it would be good to replace the elbow above the pump with a tee, and insert a thermometer using a dry well fitting.
I'd look for some dryer wood and see how it runs.

Any suggestions on where I could get some additional information into doing something like this. I know a lot of you guys are probably just familiar enough in this realm to know what you need to do but I’m certainly not there yet. Thanks.

 

[Brad001]

This does sound like wet wood. That thing will be an inferno inside with the blower fan running and a load of dry wood on top of coals.

You need to be able to see the temps if you’re going to get to know the thing; and you need to get to know it or you will hate it.

You could get a little digital probe thermometer like an Inkbird or comparable on eBay. Some have waterproof probes that you could probably drop into the top of your Hardy vent to get a spot on reading; brewers/moonshiners do it all the time. A more permanent install would be to wrap the probe to the supply port on the back of the Hardy and insulate it. Note the difference from the direct water reading as it will be less.

That will get you miles ahead of where you are now. You can burn green wood in these things but not very well unless it’s sparingly mixed with dry.

I run mine at 170 blower on, 180 blower off.

You’re right about needing to get to know the unit. I’m in full blown learning mode but I can see how not really understanding it would lead to just hating it. I’m trying to avoid getting to that point because I really do want to be able to use it and maintain it.

If you have any information on how to actually install a more permanent thermometer I’d love to hear it. Thanks.

 

[Eureka]

Any suggestions on where I could get some additional information into doing something like this. I know a lot of you guys are probably just familiar enough in this realm to know what you need to do but I’m certainly not there yet. Thanks.

A temperature probe insulated and wrapped directly against a brass/iron/steel supply fitting in the back of the Hardy cabinet will read around 3-5 degrees less than what the actual water temperature is. It would be good enough for your needs I’m sure. Even a decent grill thermometer with a probe would work since the Hardy has its own temp control and knowing more is just for you.

 

[E Yoder]

A grill thermometer sounds great to me using metal tape and insulated.

 

[maple1]

So many decent surface mount options out there these days, I would not bother trying to make a new thermometer port or well.

 

[Eureka]

The chicken hatching/brewing/moonshining/bullet-making etc. hobbyists have really driven a market in these kinds of toys

 

[Brad001]

Thanks for the suggestions and advice everyone.