Newby Zone Valve Question

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Old 01-05-15, 04:46 PM
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Newby Zone Valve Question

I'm sure this is a fairly basic question but here goes:

I have a 3 zone (main floor, 2nd floor and hot water tank) oil fired boiler. My main floor zone valve seems to work intermittently (just started in the last week or two). It is a Honeywell valve and was replaced a few years ago. At some times (currently) my baseboard is constantly getting hot water and the valve is open (the lever moves freely). The heat is set on 65 and it is 70 and climbing. At other times the lever has resistance and it maintains 65 degrees. Just curious if this is a zone valve or thermostat problem. The thermostat is a digital Honeywell and probably 10 years old.

Thanks for any insight!
 
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Old 01-05-15, 04:56 PM
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Hi Mac, welcome to the forum!

Just curious if this is a zone valve or thermostat problem.
The only way to determine for sure is to do a few simple tests with a multimeter.

Do you own one and know how to use it? Or know someone who does?
 
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Old 01-05-15, 05:16 PM
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I do have a multimeter. Just point me in the direction of what I need to check.

Thanks again!
 
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Old 01-05-15, 05:50 PM
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Are they Honeywell valves? (yeah, I see they are... just re-read your first post)

Two RED and two YELLOW wires?
 
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Old 01-05-15, 05:54 PM
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If you have the V8043E variety you will have the Yellow and Red lead wires.

On the valve in question, the one that you think may be sticking open,

set your meter to read AC VOLTS.

On the two YELLOW wires from the ? zone valve, you should read 24VAC only when the thermostat is calling for heat.

So, if the handle is loosey goosey indicating an open valve and you do NOT have 24VAC on the yellow wires, it means the valve is physically stuck open. It most likely is the power head as the body itself is rarely the problem.

If the temp in the zone is well past thermostat setpoint, and the valve is still open, and you DO HAVE 24VAC, it would indicate a problem with the thermostat or the wiring.
 
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Old 01-05-15, 06:03 PM
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To rephrase,

If there is 24VAC on the yellow wires, the valve should be open.

If there is NOT 24VAC on the yellow wires, the valve should be closed.
 
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Old 01-05-15, 06:19 PM
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The valve is a Honeywell 40004850-001 (on the metal cover). I only see one yellow wire when the cover is off.
 
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Old 01-05-15, 06:34 PM
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And like clockwork it is working fine now that I'm checking it! I'll try again later and will report back.

Thanks again!
 
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Old 01-05-15, 07:48 PM
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I only see one yellow wire when the cover is off.
You must not have the "E" model then:



Then you've got the " F " model with the screw terminals on the end plate...



There are five terminals.

The ones you need to measure that are analogous to the yellow wires are the "TH" and "TR" terminals. One of the terminals is labeled "TH/TR" ... you don't need to measure that one.
 
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Old 01-06-15, 10:55 PM
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Trooper -

The valve (Type F as you mentioned) started to act up again so I checked and while the valve is open it reads 0 volts. For comparison I measured my upstairs zone which was also calling for heat and it showed 25 volts. I assume from your note that I can change the power head instead of the whole valve (?)

Thanks again!
 
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Old 01-07-15, 08:47 AM
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I assume from your note that I can change the power head instead of the whole valve (?)
Yes, typically this will fix a 'stuck open' valve as it's usually the gear mechanism that 'hangs' and not the guts of the valve itself.

40003916-048 - Honeywell 40003916-048 - Replacement Head for V8043F Zone Valves

In some cases though, (rare), it IS the valve body sticking... you will be able to tell this when the head is removed by turning the exposed shaft.

There is something else that needs mentioned though...

You said:

It is a Honeywell valve and was replaced a few years ago.
Hopefully this means that you have the 'new style' valves where the power head can be changed without having to drain the system...

You can most easily tell if you have the 'new' vs 'old' style valves by removing the cover and looking to see how many screws are holding the power head to the valve body.

The OLD style has FOUR SCREWS holding the power head and these require that the system be drained in order to change the power head.

If you have this old style you will need to also purchase a 'conversion kit' that will update the valve to the new style:

40003918-006 - Honeywell 40003918-006 - 2 Way Powerhead Conversion Kit (Water)

The NEW style has TWO SCREWS diagonally opposite each other and there are two locating 'pins' at the other two diagonal locations. This type does NOT require draining.
 
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Old 01-07-15, 09:55 AM
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Thanks Trooper. It is a replacement powerhead and has the same part number 40003916-048 that you mentioned. It does appear to have 2 screws as well as 2 locating pins. I ordered the replacement and will (hopefully) check back in one more time after successfully replacing it.

Cheers!
 
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Old 01-11-15, 12:47 PM
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Thanks again Trooper!

So far so good. I replaced the powerhead yesterday as well as my 2nd zone (upstairs) thermostat. Maintained temp throughout the house overnight.

I appreciate all of the help.
 
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Old 01-11-15, 03:52 PM
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Great! good job Mac! Thanks for the update.
 
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Old 01-03-16, 08:20 AM
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Almost the same issue

Trooper, looks like you're the expert with this stuff. My situation is almost the same as this thread shows but a little different....

I have 4 zones, using the "E" model 40004850-001. 2 zones' valves do not open (one side if pipe is hot, other side is not). When I remove the round cover on the valve and move the thermostat for each zone, the spinning plate looks like it should, with the black lever moving like to working zones. Look identical to the working zones.

Here's the kicker.... a few weeks ago I noticed the boiler pump started to leak. I have a replacement being shipped. It's an easy enough job to replace the pump, but I don't solder so the valve replacement would require someone coming out.

Here's my question.... would a weak or failing pump have any effect on 2 of the 4 zones' valves not opening? I would think not but am not sure. FYI... the 2 zones not working are farthest away form the pump, but only by a few inches.

Thoughts? And thanks in advance.
 
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