FPX Apex 42

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Mooch

Member
Jan 23, 2019
181
Jm
Hello, I have an apex 42. Has anyone had issues with the temp sensor to kick the fan on. (Snap disc) mine takes about an hour or more to kick on and cat temp is at 1100° . I've tried it with very little ash and with full ash around the same results. I feel I'm wasting alot of heating do to the blower not being on. Also can I bypass this or get a lower temp sensor? By the way the unit was new this burning season. Thanks for any help
 

Highbeam

Minister of Fire
Dec 28, 2006
20,261
Mt. Rainier Foothills, WA
Hello, I have an apex 42. Has anyone had issues with the temp sensor to kick the fan on. (Snap disc) mine takes about an hour or more to kick on and cat temp is at 1100° . I've tried it with very little ash and with full ash around the same results. I feel I'm wasting alot of heating do to the blower not being on. Also can I bypass this or get a lower temp sensor? By the way the unit was new this burning season. Thanks for any help
As I recall this is the no longer produced furnace from blaze king. No window and a 7” flue.

Might be more responses if this was posted in the boiler/furnace section of this forum where the furnace gang hangs out.
 

begreen

Mooderator
Staff member
Nov 18, 2005
98,129
South Puget Sound, WA
moving to the boiler room
 

begreen

Mooderator
Staff member
Nov 18, 2005
98,129
South Puget Sound, WA
Right you are, I had to look that one up. Moving back.
Is the snap disk in a location where you can check it to see how well it is making contact with the stove body? Sometimes they get unseated from the spring clip retainer.
 

brenndatomu

Minister of Fire
Aug 21, 2013
7,782
NE Ohio
As I recall this is the no longer produced furnace from blaze king. No window and a 7” flue.

Might be more responses if this was posted in the boiler/furnace section of this forum where the furnace gang hangs out.
You were thinking of this...almost had me suckered in too...I started to reply for OP having a FLS problem ;lol
 
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Mooch

Member
Jan 23, 2019
181
Jm
Right you are, I had to look that one up. Moving back.
Is the snap disk in a location where you can check it to see how well it is making contact with the stove body? Sometimes they get unseated from the spring clip retainer.
It's a pain to get to but that's probably a good place to start
 

begreen

Mooderator
Staff member
Nov 18, 2005
98,129
South Puget Sound, WA
It can take a while to heat up the mass of a big firebox. After the fireplace is up to temperature does the blower stay on or cycle?

If this is a standard form thermostatic snap disk, there may be one available with a lower on temp.
 

begreen

Mooderator
Staff member
Nov 18, 2005
98,129
South Puget Sound, WA
Going by the part number, it looks like the Apex 42 uses the same 120º snap disc as many other Lopi units. This thread on the topic may be helpful.
 

Mooch

Member
Jan 23, 2019
181
Jm
It can take a while to heat up the mass of a big firebox. After the fireplace is up to temperature does the blower stay on or cycle?

If this is a standard form thermostatic snap disk, there may be one available with a lower on temp.
Yes once the blower kicks on it does remain on till the unit cools. Just seems like it takes longer than we first started using it
 

Mooch

Member
Jan 23, 2019
181
Jm
Going by the part number, it looks like the Apex 42 uses the same 120º snap disc as many other Lopi units. This thread on the topic may be helpful.
Good info, thanks
 

coaly

Fisher Moderator
Staff member
Dec 22, 2007
4,737
NE PA
Hello, I have an apex 42. Has anyone had issues with the temp sensor to kick the fan on. (Snap disc) mine takes about an hour or more to kick on and cat temp is at 1100° . I've tried it with very little ash and with full ash around the same results. I feel I'm wasting alot of heating do to the blower not being on. Also can I bypass this or get a lower temp sensor? By the way the unit was new this burning season. Thanks for any help
Most thermal activated switches are marked with a F for Fan Switch which are normally off, and turn on with temperature rise. (controls blower) A temp switch with an L is a Limit Switch which is normally on, and turns off with temperature rise. (controls burner)They usually both have a number which is the preset temperature where they activate. As the fan switch cools down it will open at a predetermined temperature drop. This off temperature may not be desirable as well. Adjustable fan switches have a “on” setting to turn on with temperature rise and a cut off setting to be able to control the temperature where the fan shuts off. They are larger, more expensive and may not physically fit within the application. The only way to change preset snap disc switches is to move the switch to sense the temperature differently, or use a switch with a different temperature setting.

How they work is the expansion and contraction with heat causes a thin metal sheet attached to the housing of the switch to pop in or out, since it can’t move where attached to the housing. The center can only move convex or concave, arched like the bottom of a soda can pushing on a micro switch.

If you put the two wires together it will bypass the switch, running the blower constantly. Removing power will operate as a manual control.
 
Last edited:

Mooch

Member
Jan 23, 2019
181
Jm
Most thermal activated switches are marked with a F for Fan Switch which are normally off, and turn on with temperature rise. (controls blower) A temp switch with an L is a Limit Switch which is normally on, and turns off with temperature rise. (controls burner)They usually both have a number which is the preset temperature where they activate. As the fan switch cools down it will open at a predetermined temperature drop. This off temperature may not be desirable as well. Adjustable fan switches have a “on” setting to turn on with temperature rise and a cut off setting to be able to control the temperature where the fan shuts off. They are larger, more expensive and may not physically fit within the application. The only way to change preset snap disc switches is to move the switch to sense the temperature differently, or use a switch with a different temperature setting.

How they work is the expansion and contraction with heat causes a thin metal sheet attached to the housing of the switch to pop in or out, since it can’t move where attached to the housing. The center can only move convex or concave, arched like the bottom of a soda can pushing on a micro switch.

If you put the two wires together it will bypass the switch, running the blower constantly. Removing power will operate as a manual control.
Thanks for clearing that up. I did find a new disk with a lower temp of 104° rather than 120° hoping that will work. And if that doesn't fix it i will bypass it. My last stove had a switch that you could select from auto or manual, they all should be that way. Will find out next season.
 

coaly

Fisher Moderator
Staff member
Dec 22, 2007
4,737
NE PA
If the lower temp switch comes on too soon, mount it on standoffs or hang it farther from the surface until it senses the temp you want it to come on. You don’t want it coming on too early preventing the firebox temperature from coming up to a cleaner burning temperature zone before extracting too much heat from it.
 

Mooch

Member
Jan 23, 2019
181
Jm
If the lower temp switch comes on too soon, mount it on standoffs or hang it farther from the surface until it senses the temp you want it to come on. You don’t want it coming on too early preventing the firebox temperature from coming up to a cleaner burning temperature zone before extracting too much heat from it.
Ok I will try this. Thanks
 

begreen

Mooderator
Staff member
Nov 18, 2005
98,129
South Puget Sound, WA
The snap disc on this unit is normally open. It closes on temp rise to engage the blower. 104º is pretty low. I would consider 110º instead.
 

begreen

Mooderator
Staff member
Nov 18, 2005
98,129
South Puget Sound, WA
Correct. First verify that it is making good contact. You could also try painting it black.
There should be a snap disc in that format in the 110 or 115º on temp. It may not need the terminals coming out of the sides at a 90º angle if there are good clearances to them when the switch is installed. That may open up more options.
 

Mooch

Member
Jan 23, 2019
181
Jm
Correct. First verify that it is making good contact. You could also try painting it black.
There should be a snap disc in that format in the 110 or 115º on temp. It may not need the terminals coming out of the sides at a 90º angle if there are good clearances to them when the switch is installed. That may open up more options.
They are cheap enuff I'll buy a couple different Temps to see which one works best. Just seems like a lot of heat wasted till it kicks on. If it was a free standing stove probably wouldn't matter as much but with a ZC you don't get much radiant heat. As soon as the blower comes on it warms the room almost instantly.
 

begreen

Mooderator
Staff member
Nov 18, 2005
98,129
South Puget Sound, WA

mjbroz

Member
Mar 6, 2018
14
WA State
Here is what I did for my Apex 42. I suppose begreen could be correct about cooling the firebox, but my impression is the fan is not significantly impacting the firebox temp. I picked up a manual switch that allows me to run it "manual on" mode or "auto on/off" mode. I mounted it in the lower grill using a factory gap in the face (no drilling required). Please note: I'm not a professional electrician; if you go this route, please do your own research and/or consult a professional.

Details:

My problem is the fireplace take a long time to decide it is hot enough to turn on the fan (and there is no manual override). The basic issue seems to be the thermostat sensor is on the bottom right corner and things like ashes, etc. can make it so that the thermostat does not kick in for a long time (can take over 30 min with the stove at 600 degrees according to the little read out).

Based on this, I wanted to be able to over ride the default, but I really like that it will automatically turn the fan off after I go to bed and the stove cools down.

So, I picked up a toggle switch with 2 "on" settings that handles 2 circuits per side:


image(1).png


As you probably already know, the 2 center tabs are the "out" terminals (no matter which setting the toggle is set to). The 2 tabs on the left are "in" and will be connected to the center tabs when the toggle is positioned left. The 2 tabs on the right get connected to the center tabs when the toggle is positioned right.


So, this allows me to have 2 separate circuits entirely. I'm sure I don't need this, but it keeps it clean in my mind.

There is easy access to the two wires that hook to the sensor. This is how I hooked up the switch (the left "down" arrow is the hot lead, and the right "up" arrow respresents the neutral/ground side):

image.png


In "manual" mode, I bypass the temp gauge entirely (it should be totally isolated from power). In "auto" mode, the "in" and "out" wires to the temp gauge are hooked up like before.

This setup has been working for the past 2 years or so.
 

begreen

Mooderator
Staff member
Nov 18, 2005
98,129
South Puget Sound, WA
This could be done by using a single-pole single-throw switch. It would simply jump out the snap disk thermostat to make it manual on. Turning off the switch would have it revert to the snap disk. Be careful doing this as this is line voltage.
My preference would be to replace the snap disk with one that has a bit lower "on" temperature or maybe relocate the snap disk?
 
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Mooch

Member
Jan 23, 2019
181
Jm
Here is what I did for my Apex 42. I suppose begreen could be correct about cooling the firebox, but my impression is the fan is not significantly impacting the firebox temp. I picked up a manual switch that allows me to run it "manual on" mode or "auto on/off" mode. I mounted it in the lower grill using a factory gap in the face (no drilling required). Please note: I'm not a professional electrician; if you go this route, please do your own research and/or consult a professional.

Details:

My problem is the fireplace take a long time to decide it is hot enough to turn on the fan (and there is no manual override). The basic issue seems to be the thermostat sensor is on the bottom right corner and things like ashes, etc. can make it so that the thermostat does not kick in for a long time (can take over 30 min with the stove at 600 degrees according to the little read out).

Based on this, I wanted to be able to over ride the default, but I really like that it will automatically turn the fan off after I go to bed and the stove cools down.

So, I picked up a toggle switch with 2 "on" settings that handles 2 circuits per side:


View attachment 304078


As you probably already know, the 2 center tabs are the "out" terminals (no matter which setting the toggle is set to). The 2 tabs on the left are "in" and will be connected to the center tabs when the toggle is positioned left. The 2 tabs on the right get connected to the center tabs when the toggle is positioned right.


So, this allows me to have 2 separate circuits entirely. I'm sure I don't need this, but it keeps it clean in my mind.

There is easy access to the two wires that hook to the sensor. This is how I hooked up the switch (the left "down" arrow is the hot lead, and the right "up" arrow respresents the neutral/ground side):

View attachment 304080


In "manual" mode, I bypass the temp gauge entirely (it should be totally isolated from power). In "auto" mode, the "in" and "out" wires to the temp gauge are hooked up like before.

This setup has been working for the past 2 years or so.
That looks like it will work great. I did end up going with a lower temp snap disc and it has been working perfectly. Also when I took the old snap disc out it has rivets holding it in thus making a small gap from bottom of fire box and disc. On the new disc I ground down some of the new rivets so it was in full contact with the bottom of the fire box