problem with the thermostat or aquastat relay (Honeywell L8148E)

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Old 04-13-13, 06:14 PM
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problem with the thermostat or aquastat relay (Honeywell L8148E)

I have a Honeywell L8148E aquastat relay; forced hot water gas boiler. it will not come on. when jumping TV to T it will not come on. Does this mean I have a problem with the thermostat or my aquastat? What do i need to do to troubleshoot further? Here is more info. The vent damper opens and furnace fires up when jumping Z to the wire connection that comes off the bottom outside of the component housing the high limit dial.

Here is a diagram of what I have = see figure 3 at http://techlit.honeywell.com/techlit...0s/60-2278.pdf . The wiring has been changed a bit by the previous home owners to accommodate for the damper. Here is the change: vent damper wiring harness into aquastat relay is as follows: black to TV, brown to Z, yellow to RD, orange to the screw for wire that comes off the bottom outside of the component housing the high limit dial.
 
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Old 04-13-13, 07:23 PM
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when jumping TV to T it will not come on
And the 'switching relay' does not 'click'?

It sounds like the aquastat has a problem.

It's not the thermostat.
 
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Old 04-13-13, 07:48 PM
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thanks for the response

when jumping TV to T the switching relay does NOT click. however, the switching relay DOES click when when jumping Z to the wire connection that comes off the bottom outside of the component housing the high limit dial. in the attached photos you can see the jumper wiring that allows me to temporarily fire up the heat.

i have a new aquastate to install, but want to make sure this is the problem before diving in. also, it has a male/female connection for the damper wiring. so, i guess I have to get a new wiring harness. not sure if I can rewire it like the existing aquastate. or, just put the jumper in the aquastate and leave the damper in the open position and loose a little efficiency. the later feels like a bandage because if I ever decide to sell the house new buyers will give me a hard time and request hooking up the damper.

thanks for additional input - Doug
 
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Old 04-14-13, 08:23 AM
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the switching relay DOES click when when jumping Z to the wire connection that comes off the bottom outside of the component housing the high limit dial.
I don't see how that is possible.

I do understand why the damper would open and the burners fire, but to have that jumper operate the relay is not possible.

CAUTION!

Installing the jumper as you have described is BYPASSING THE HIGH LIMIT SAFETY CONTROL!

Leaving that jumper in place means that there is NO CONTROL over the boiler temperature!

You are essentially hard wiring the burners in an ON state... Do NOT walk away from the system with the jumper in place.

Fair warning to the wise!
 
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Old 04-14-13, 08:43 AM
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i guess I have to get a new wiring harness
BEST CHOICE.

This MAY be the one you need, VERIFY before purchasing!

Patriot Supply - 46356900

not sure if I can rewire it like the existing aquastat
You could, if you understand exactly where and how to wire it.

leave the damper in the open position
Agreed that this is not a good option.
 
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Old 04-15-13, 11:36 AM
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thanks for your help. my family and I very much appreciate it! I replaced the aquastat relay, which required me to replace the wiring harness. everything works fine now. waited until Monday in case I ran into problems and needed to call someone.
 
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Old 05-14-13, 11:36 AM
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Wink Similar Issue: Boiler box won't fire ... unless....

Drag when you need to retype the entire post after unknowingly timing out.

Similar issue. Crown boiler seems to be operating 100% fine, except the flame won't fire. Lightly adjust the burner B1 and/or B2 wires and box fires up fine. Touch to the terminals (ie lineman), box fires up fine. Might stay on for 5 minutes, or 5 hours. Connection drops, however, on its own.. no reason identified.

Post connection for B1 is on tight, appears clean.
Terminal connection for B2 is on tight, appears clean.
Sensors appear to be ok (via voltage checks or bypass jumps)

Bit of reading (like post above) suggest the entire Honeywell Aquastat might need to be replaced. No way of fixing? Seems like a fix would be relatively minor.

In the event a full replacement would be needed, anyone have an educated guess on the costs of the Honeywell Aquastat L8148E; I'll likely do the replacement myself. Would consider a contractor doing replacement if pricing would be reasonable (any guesses on reasonable pricing for contractor to swap?).

Thank you everyone,

-pr
 
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Old 05-14-13, 03:43 PM
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Hi Rogue,

I believe that if you were to remove the aquastat and separate the circuit board from the case, you would probably find a cracked solder joint somewhere on the board.

Do you own a soldering iron? Do you know how to use it? If so, and you want to give repairing it a go, we'll give you some more tips. You've got nothing to lose, right? I mean, it's not working now anyway.

It's an easy enough job to replace yourself if you decide to. A contractor is going to mark up the price of the aquastat two or three times, plus labor. Cost you at LEAST $500 bucks I bet. You can buy the aquastat for about $150 or so.

Take a look at your aquastat again and see if you can find a 4 digit 'suffix' part number. It may be stamped with black ink on the board, or the case... take a mirror and look on the BACK of the case as well. There are different 'flavors' of this control and it's important you get one that will work with your system.

PEX - Radiant Heat - Radiant Heating - Plumbing Supplies - PexSupply.com

Does your aquastat have a plug-in VENT DAMPER on it? (vent damper is on the flue pipe leading to the chimney.
 
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