# Some advice for an overheating Aquatherm..............



## NYsignman (Jan 5, 2015)

Guys,

First post but 7yr Aqua-Therm 145 owner......here's what I need help with.....  Boiler is outside in shed, approx 90ft from house, down hill (slight).  With outside temps up and down this winter, I've been having "boiler over" issues this past year, after just running with straight water, instead of 50% glycol.  Have been setting aquastat between 160-170 to compensate for ambient temps.

Have a stacked plate exchanger at inside hydronic oil boiler, and use the existing baseboard loop as a constant dump zone with constant running taco 007.

Temp. relief valve has been going off and would like to create a expansion/dump zone at boiler site....or believe that's what I need to do?  If heat isn't being used over period of time, it just gets to be too much, no matter what I set aquastat to.

What do you need from me to help figure this out?  I've read a bunch of articles and have fine tuned this system over past 4yrs (inside and outside).....but would like to fix this.

My 145's capacity is 48 gal......and have about a 90ft run of 1" pex loop.  Pressure relief (30 lb) and temp relief valves (210 blow off) are in place.....

Can I just put a tank (how big if yes?) above highest pipe point, remove temp relief valve, and pipe up to that to let water expand up there and then let gravity feed back down?  Or???

Thanks for your time to look at this!  I appreciate any help possible.


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## atvalaska (Jan 5, 2015)

I got my 275 aq at 165 and 12 diff = no more boil overs (easy winter thus far)> after 7 years u got to have "loading" down by now?!  I load mine log to left and right of center /coals in between "looks like a C on its back as each log burns,  the next one "rolls in" I split nothing, and they are all  36/38" long.... good stuff on your boiler here to >  outdoorwoodfurnaceinfo.com/


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## atvalaska (Jan 5, 2015)

""210 blow off""  i'd check that ...mine "blows off " at 203...and its brand new  ...I need one made by NASA


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## Bob Rohr (Jan 5, 2015)

NYsignman said:


> Guys,
> 
> First post but 7yr Aqua-Therm 145 owner......here's what I need help with.....  Boiler is outside in shed, approx 90ft from house, down hill (slight).  With outside temps up and down this winter, I've been having "boiler over" issues this past year, after just running with straight water, instead of 50% glycol.  Have been setting aquastat between 160-170 to compensate for ambient temps.
> 
> ...




What size expansion tank do you have?  Remove the black cap. Underneath it looks like a tire stem on the tank.  Push it in for a second, do you get air or water?

If it's water the expansion tank is waterlogged.  If it is a bladder type, probably needs to be replaced.  Your pressure should not change more than 10 lbs or so between cold start and max. operating temperature.

One relief valve is a 210° 150 psi, T&P valve like a water heater has, probably, the other is a 30 psi pressure only.  Which is tripping?  If it's the T&P you have probably exceeded the temperature rating.  If it's the 30 psi, it a pressure problem related to expansion.

Usually once a T&P valve releases on temperature it needs to be replaces, they don't generally re-seat.

Go to Amtrol.com and use the free calculator to size the tank, most times those Aquatherms have undersized, or grossly undersized expansion capacity.

Here is an example using 65 gallons of total system capacity, 50- 210° operating temperature, 15 psi fill pressure.


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## Pat53 (Jan 5, 2015)

make sure your feed door and ash door or closed tight and the gasket seals are in good shape. I had an aquatherm years ago and I remember having to change the door gasket more than once. If the gasket is leaking it will keep the fire burning and may be causing your overheat problem?

Pat


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## NYsignman (Jan 6, 2015)

ATV.....I have to verify the temp blow off valve amount.....I assumed 210, but haven't been there (when happening) to see actual blow off temp.  That's the only valve I haven't replaced since new, and would say that it's blown off approx. 10 times in 7 yrs.

I also have the aquastat at 165 with a 12 diff......at least today I do.  Have had it around 160 to 170 for most part.....but last year (and yrs before) when antifreeze was in, I never ran it below 180 with same diff.

Pressure valve has been replaced and never blows unless overfilled.

This year was the first to run just water, because of cost of antifreeze and blow off issue, then wait time to cool off to fill boiler back up.....so just did water (manual fill inside house tied into return loop) and did notice that it was hotter and held temp better, but again, came up in temp faster too.

Bob....It's the stock bladder tank that came with setup (normal size for most residential boilers that I've seen)......I'll verify it's not waterlogged, and haven't had pressure issues, so my assumption is a tired T/P valve, or just can shed the heat when I don't call for it in longer periods of time.

I just did a search for the Amtrol tanks you showed from their calc........man... they're expensive!  I can see what you mean by mine being undersized!  Unfortunately, that's where I have to usually make my things work, or go outside the box to use/adapt something for me.

Pat......I haven't replaced the gasket from new, so that may be helping the upper temps.

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I have a room in house that can't be heat satisfied, IE, 2 small wall rads, full wall of windows, older build and on slab with slate floor.  This is where I also have a fireplace insert that I run also during winter.  I have fine tuned the running of boiler and running of fireplace, by moving my single thermostat into my bedroom (was in hallway) and buffer that by shutting my bedroom door...........long periods of door shut and not calling for heat, puts me in that boiler over situation......this is where I'm looking for a long term solution for the boiler over issue.

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Maybe first I should replace the T/P valve and see if it's the main culprit?  Is it anything special that can't obtained from parts house? * IE, what are the specs for this Aqua-therm valve?*

Thank you for taking the time to offer your help....I appreciate it.


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## woodsmaster (Jan 6, 2015)

Sounds like your door seals aren't snuffing the fire out. I'd replace them. 7 years is overdue for any seals I've ever used.


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## maple1 (Jan 6, 2015)

Are you sure it's temps, and not pressures, that is sending the water out? Don't think you've said anything about actual observed temps & pressures?


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## NYsignman (Jan 6, 2015)

WMaster........OK....I agree, I'll change that and the old T/P valve.  I do remember it dripping at bottom of door when using damper wood, so it's been crushed down there at least.

Maple.............def. Temp valve issue......there's 2 relief valves and the one that's hot (after expelling water) is the Temp Relief.

I run this about 15 lbs when hot and don't have any issues with pressure....until long after it's been boiled over (if away or not seen for hours) and below circ. level.....besides smoldering wood/coals to keep temps up...bringing up the pressure over 30 lbs

Thanks


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## brant2000 (Jan 6, 2015)

NYsignman said:


> I run this about 15 lbs when hot and don't have any issues with pressure....until long after it's been boiled over (if away or not seen for hours) and below circ. level.....besides smoldering wood/coals to keep temps up...bringing up the pressure over 30 lbs



You mention that it's 15 PSI when hot, but also over 30 at times.  The pressure will continue to rise in your system, with respect to temperature.  The ability for the system to accommodate a higher temperature with less of a pressure increase completely depends on the system's expansion capacity.  If you're getting over 30 PSI at any normal operating temperature, you don't have enough expansion capacity.


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## NYsignman (Jan 6, 2015)

Bryant......it never sees 30 lbs until *long (hrs)* over boiled and can't circulate from temp relief valve removing enough water to stop circulating.....never in a normal heat cycle........15-17 max at full temp aquastat shut down.


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## Vinced (Jan 6, 2015)

You have a bad relief valve or you have an air leak at your main door, ash auger door, or your damper flap isn't seating. I've had my AQT 145 for 8 years and the only time it boiled over is when the door was not shut tight. I've left town for 5 days in the winter and turned off everything that takes heat off the boiler and had a neighbor check load the boiler everyday and it never boiled over. It shouldn't boil over from not enough heat being drawn off it. I use straight water in mine and run it 15-18psi at 185-190 top temperature. I adjust the aqua stat  temperature differential depending on the outside temperature.


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## Bob Rohr (Jan 6, 2015)

Vinced said:


> You have a bad relief valve or you have an air leak at your main door, ash auger door, or your damper flap isn't seating. I've had my AQT 145 for 8 years and the only time it boiled over is when the door was not shut tight. I've left town for 5 days in the winter and turned off everything that takes heat off the boiler and had a neighbor check load the boiler everyday and it never boiled over. It shouldn't boil over from not enough heat being drawn off it. I use straight water in mine and run it 15-18psi at 185-190 top temperature. I adjust the aqua stat  temperature differential depending on the outside temperature.


good point on the gaskets.  I've also seen the doors warp from excessive heat when they boil off and are dry firing.

The T&P is a standard "off the shelf" 3/4" found at most plumbing and box stores.  Watts 100 XL is most common @ $10- 15.00.   Make sure the probe is into the tank, don't use extender fittings.


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## NYsignman (Jan 6, 2015)

I ordered new door and ash gaskets and new T/P valve....should be here by Thurs.  Called buddy who sold this to me (10 yrs ago actually) and discussed these issues I've mentioned....his first suggestion was the door gasket too.....I'll advise sometime this weekend after replacing these gaskets and T/P valve.

Thanks for all of your help.


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## NYsignman (Jan 6, 2015)

I ordered the door and ash gaskets, and a new T/P valve..........Aqua-Therm spck'd Cash Acme 210 deg. off x 80 lb off..............called buddy/dealer who sold me this (actually 10 yrs ago now!) and first thing he said was door gasket too!

I'll update after parts come in and I install (end of this weekend most likely).

Thanks guys for all your help


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## buck0123 (Aug 8, 2015)

NYsignman,

What did you use to hold your aquatherm door seal on? I have to replace mine.

Thanks,
Bill


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