Heating Issues

zvalve

<span style="font-size:12pt">I am heating my two story house with a Dunkirk hydronic boiler using 2 (Honeywell) zone valves connected to LUX and Honeywell programmable thermostats, a Honeywell aquastat and a Taco circulating pump. During the day the boiler doesn’t fire when you raise the temperature to 80 and a jumper across the t-stat terminals of zone 1 t-stat (LUX) doesn’t cause the boiler to fire. There are 24 volts across the terminals of this t-stat. The room is around 65 and the program is set at 67. In the morning around 6:30am with the room at 65 and the program at 67 the heat was on and the radiators are hot but the boiler was not firing. I assume it must have fired and then shut off because the lines in and out of the zone valves were hot. I have been living in the house for about seven years and the heat has been OK although at times it seems weak or not working. I am just learning about these systems so forgive me if I am making some stupid mistake but I have the following questions because I think there is something amiss.   </span>

<span style="font-size:12pt">1. What is going on here?</span>

<span style="font-size:12pt">2. Is the aquastat ok?</span>

<span style="font-size:12pt">3.  Are the zone valves or t-stats incorrectly wired in series?</span>

<span style="font-size:12pt">4.  Could there be a hidden shut off timer in the system so during the day the boiler is turned off?</span>

STEVEusaPA

could be any of the 4

Your best bet is to bring in a pro to look everything over, check continuity, voltages, amps and troubleshoot the entire system

Zman

Zone Valves

I would first suspect the zone valve power heads. The Honeywell valve will get tired and the end switches will not close even though the valve is open. This means that zone cannot call for heat from the boiler. The zone will heat if another zone tells the boiler to fire, Chances are you need to change the zone valve power head. You can test this by jumpering wires connected the red wires on the zone valve. If the boiler fires, you have found the problem.

zvalve

Heating Issues II

Thank you Zman for the advice, I will try that. By jumping the red wires on the zone valves you are tripping the microswitch?  Is that correct? When you use the term power head on the zone valve do you refer to the geared motor or the motor and external parts the motor is turning?

zvalve

Heating Issues Revisited

Steve

Good advice but pros cost big bucks and I want to learn more about these systems. Do you know how the pros would use amps to troubleshoot the system and issues described. Perhaps I just need to replace the zone valves?

Zvalve

Zman

Yes

By connecting the wires attached to red, you are simulating a closed microswitch. If the boiler fires, the microswitch is not working.

Most people will replace the entire power head assembly (everything but the brass valve)  as it is easier. I have found it is usually just a weak motor. That part can be replaced if you want to save a few bucks.

Carl

zvalve

Heating Issues & Wiring

Figure 8 in the aquastat literature and Figure 13 in the 8043E zone valve lit show wiring diagrams. So to simplify only 2 sets of wires from the thermostat  and 2 from the transformer would be necessary to energize and regulate the zone valves but I counted six in my system. What could this indicate?

Zman

Wiring

I am not clear on how yours is wired.

Figure 8 shows 2 valves and t-stats wired to the aquastats transformer and 1 to another transformer. You can only power 2 valves off the aquastat do to the size of the internal transformer.

Figure 13 shows all the valves wired off one external transformer.



The red wires which are connected to the switch inside the valve are the ones I am referring to.



Carl

zvalve

Heating Issues and Wiring

Carl

There is an auxiliary transformer which I believe supplies the thermostats but I would have to check to confirm. So I have  2 zone valves and 2 transformers with one in the aquastat. With 2 zone valves and 2 thermostats do you need two transformers?

Joel

Zman

VA

Joel,

On the transformer side of things, each of your zone valves requires 7.68 VA.

The aquastat is capable of supporting 2 zone valves with no external transformer.

your transformers will have a rating (often 40 VA) that will tell you what you can attach to it. I don't see why you have any external transformers.

The transformer has very little to do with the function of the end switches. They are two separate circuits.

Carl

zvalve

Heating Issues & Wiring

Carl

I have a questions. Does VA stand for VoltsXAmps or voltageXcurrent? Is that also watts? The microswitch and the motor in the zone valve gets common power from the aquastat? Where does the thermostats get their power from? Is the voltage across all these devices 24 Volts?

thanks Joel

Zman

VA

A VA is a watt, so volts X amps=watts (or va). In the theoretical EE world there is a difference but not for us.

The aquastat has a transformer that powers the end switches and attached relay(s) and up to two honeywell zone valve motors and the attached t-stats.

It sounds to me like the external transformers are powering the t-stats and the squastat is powering the end switches in your case.

If you post a sketch of what you have I could tell you for sure.

Essentially, you have one circuit that has a t-stat (switch) wired to a load (zone valve motor). This circuit make the valve open.

The you have another circuit with and end switch (switch) connected to the relay and the aquastat (load) which opens and closes the contacts to the boiler and circulator.

Carl

zvalve

Heating Issues & Wiring

Carl

I will take some pictures when I get home from work and post them.

Joel

zvalve

Heating Issues & Wiring

 Carl

How to you put pictures within the post content? Attached are wiring photos and the transformer at the boiler.

Joel

Zman

Wiring

Joel,

That is a pretty normal way to wire a boiler. It is kind of ugly from an esthetic and troubleshooting point of view, but should work just fine.

You can tell if the valve is opening correctly by sliding the lever back and forth. An open valve will have no resistance when you slide the lever.

If the micro switch is working correctly it will close the connection across the to red wires which tells the aquastat to the boiler to fire.

If you jumper the black and white wires connected to the red wires you can test this function.

Those Honeywell valves are notorious for the problem you are experiencing. As the motor gets tired it no longer opens the valve far enough to trip the switch.

Just replace the head and be done http://www.pexsupply.com/Honeywell-40003916-026-Replacement-Head-for-V8043E-Zone-Valves-8632000-p



Carl

zvalve

Heating Issues

Carl

Thanks. I checked the motors and they seemed OK but one the the valve's microswitch was no good so I replaced the power head with an honeywell V8043E 5000 series power head I bought at Lowe's. Is that OK? The heating system seems to be much better anyhow.

Joel

Zman

Sounds good

I am thinking the head you found is working just fine.