Verify my wiring to my boiler.

I have just bought a house built in 1996 that has an in-floor radiant heat system. We had to put in a new boiler and now I need some verification that I have wired the thermostat/actuator/controller correctly. I am attaching some pictures and a diagram to depict the situation I have as it is now. I am a bit concerned because the central heating call seems to be cycling pretty quickly every 5 minutes or so even though the zones are not calling for heat. (Near as I can tell anyway.)

I have several questions but I'd like to start with simply: Is the wiring correct in the wiring diagram I am attaching?

 

You would probably be better served in the boiler forum.

 

I moved your thread to the boiler section.

I have a question.... on your thermostat you show an R, W and a B connection. What is B ?
That doesn't appear to be correct with this type of heating system.

 

What is that 'controller' item you show?

what is the MODEL of the thermostat?

What is the model of the boiler?

 

B = blue refers to the color of the wire rather than any function it may be performing.

 

ah the "controller".... that's what the previous owner wrote on the wire coming from the boiler. I took a closer look where the wires come in (at the boiler) and found a transformer (AT150F 1022) which then connects to the boiler.

 

If it was only a transformer, there would be only two connections.

Is it a transformer AND a 'relay' device?

 

I had a hard time finding anything on the thermostats. They are the old style round ones with the makers name emblazoned on the front...WIRSBO. I could not find anything about this tstat...even when just looking at images. It wasn't until I decided it sure looked a lot like a Honeywell tstat that I got out the magnifying glass (!) and discovered the word "Honeywell" in tiny letters on the front below the Wirsbo name. Thanks a lot Wirsbo. So its a Honeywell 3-wire thermostat.

 

The boiler is Prestige Excellence.

 

Regarding the transformer...I can't really see what's going on there with connections to the wiring without opening it up. Something I'm not comfortable (read desparate enough) with just yet. I am attaching a picture of it.

 

Yeah, that's just a transformer, not what I was thinking... so those extra terminals are still just a mystery.

That black wire visible in the pic appears to be coming out of that box and it touching the pipes. What is that black wire?

The Beaver asked if you could take a few more pics... he wants to know if that expansion tank is hanging on the end of that 1/2" pipe with no support.

 

I presume that since the valves and things are wired the way that they are...

that the boiler does NOT include the "Optima" control module?

Did you install the boiler? or a contractor?

 

First of all, thanks for responding to my query. There is just nothing like someone who actually knows what they are doing.

I am a retired "Systems Analyst" (mainly computer systems) who is probably a bit obsessive when it comes to do-it-yourself. Undaunted by the fact that I know nothing about any of the components of this heating system nor how they interact, I set out to get my heating system working at its best with winter coming on.

The previous owner left me with quite a mess. There are two manifolds of six actuators each which are connected to four tstats making 2 zones upstairs and 2 zones on the main floor. Some work fine, some intermittant and others (it turns out) don't work at all. The interface among the tstats, actuators and boiler consisted of a tangle of wires that the boiler installer took one look at and said....well, that's going to take some time sorting out. Uh oh, dollars flying out the window in expensive tech time. Hell, I can figure this out.

I should mention that my daughter is getting married next weekend and we have family flying in from hither and yon and it sure would be nice to have some heat in the house. The glare of my wife will likely not be enough to heat all four zones.

So I dive in. Believe me....long story made short.... I thought I had things working just peachy until I went down to the boiler and watched it for a while and noticed that it was cycling every few minutes with a central heat call even though I had turned down the tstats and hey, what are you talking about? I'm not calling for heat! So I had to question the wiring at this point. Did my some research and got schematics and they matched what the PO had wired up. But my confidence in the basic wiring was shot. Thus my original post.

In my troubleshooting I began eliminating any complexity so I disconnected all the wiring and indeed the boiler got the message and quit cycling. It went to Standby. It must have detected nothing attached to its tstat circuits. I wired in one tstat and one mva. Back to cycling!! What? I forget exactly what happened next (I'm sure it will all come out in therapy). But eventually I got tired and left the manifold with only one mva installed and wired in to one tstat...cycling be damned.

I woke up at 2am in a sweat. The temperature was 85! What? Thank god the wife is out of town for a few days. So I'm tromping around in my underwear trying to figure out what the boiler is thinking. I investigate the manifold where the one mva is and it is 110 (I have a temp gun that I use for my outboard motors.) Holy ****!

Turns out if you remove the mva from the manifold it leaves the valve open. Open valves (for some reason) results in the boiler going into this short cycling call for heat. Thats how you get to 110 at the manifold. Further turns out that a couple of my tstats are stuck open. So even when they were screwed on, they were causing the cycling too.

Hmm...wonder what these black caps are for? The ones I found in the manifold closet. Turns out they are not just to keep things neat and clean, but when you screw them on (completely) they close the valve...relieving the boiler from the need to cycle. That was a major discovery!

I now have things wired up and running nicely at 69 degrees. I'm happy, the wife's happy and impending doom has been thwarted once again.

There is a remaining question as to why I am losing system pressure at the boiler. It is dumping quarts of water (over the course of a day) out one of the drains that go outside. Turns out the valve that is suppose to automatically keep the pressure up was/is stuck. I have to manually open it up a bit to allow more pressure from the main water supply to keep the pressure in the 10 to 15 psi range. I don't plan on working on this. I'll let the tech figure it out when he fixes/replaces the stcky valve and does annual maintenance next week.

Where's my tux?

 

I'm glad you got the wiring issue straightened out as I was looking at your first picture again and am mystified by the custom built "control" board. The yellow wires are the zone motors which appear to be all connected together which would mean they would all work at the same time.

 

I have not taken the jacket off the boiler. (Drawing the line there for now at least.) So no telling what controller is in there. I do think I could probably use a couple of these to get the wiring under control at the manifolds.

https://www.uponorpro.com/~/media/Ex...spx?sc_lang=en

Contractor installed the boiler.

 

Indeed you are correct. Only one tstat is wired in because I'm not sure how to wire in the other one. I think it's straighforward but not confident enough to wire it up yet.

 

I was actually thing more along the lines of the Taco zone control panel... in a box with a cover, and includes transformer.

Taco Zone Valve Controls , Control of Taco Zone Valves , Taco ZVC Valve Controls - SupplyHouse.com

At this point we need to discuss that 'wiring board' that PJ brought up (I've bit my tongue on that so far), and actuator power requirements, etc.

As I understand it, correct me if I'm wrong:

You have FOUR zones total,

UPstairs you wish to activate FOUR MVA simultaneously as one zone, and TWO MVA as the second.

DOWNstairs you also have two zones with actuators split three and three.

I haven't looked yet at the current draw of the MVA actuators, but what you need to be concerned with is just that.

Depending on the thermostat capability, it may or may not be rated for the current that multiple actuators will draw. That's why knowing what thermostat is there is important.

The transformer you have installed is presumably for power ALL of the actuators.

The AT150 transformer is rated at 50 VA . Again, without having yet looked at the specs on the MVA, it is PROBABLY not enough transformer. If all 12 of the actuators need power at the same time, which could happen, it could burn out that transfomer. If the MVA actuators draw only 4 VA each, which is possible I guess, you could be OK with that.

I have some thinking to do on this, but I'm getting the heated glare from my spousal unit who wants me to get off the computer and do some chores.

 

I have two expansion tanks that are hanging from 1/2 inch pipe. Should they be strapped in? I'll ask the boiler maintenance tech about that since he installed them. From what I have been reading, they may be water-logged and related to the loss of pressure situation.

The Beav...he just hasn't ever been the same since he got his head stuck in that fence and we had to call out the fire department to get him out.

 

According to this spec sheet for the MVAs, I should have a 100VA transformer. I'll have to talk to the boiler tech about this too. Sounds like he didn't give me the right transformer.

Motorized Valve Actuator (MVA), Four-Wire: A3020522

 

Why two? If that pipe I can see the end of is what the tanks are hanging on, yes, there should be some support on that pipe.

Can you take some pics showing the entire boiler installation? I'd like to see the guys work.

Did you read this?

http://www.doityourself.com/forum/bo...sion-tank.html

You say there is a pipe going outside? Can it freeze? It would be VERY VERY BAD if that pipe is from the pressure relief valve and it could freeze.

Or two 50s. One powering one manifold, the other the other.

Was your installer's name Lumpy by any chance?

 

There's more than one?

If the other one is the 'condensate drain' then it too must not be subject to freezing.

 

Lumpy ?!?!!!?! .................. No. Eddy.

 

Here is a picture of the boiler

 

I believe I understand why there are two expansion tanks... the small one is for the domestic hot water and the larger one for the heating system.

What about the multiple drains going outside? Can they freeze?

 

Here is one possible way to wire your valves:



This puts the load of only one valve on each thermostat.

Thermostat opens first valve, first valve opens second valve, second valve opens third, etc., last valve fires the boiler.

Some may consider a few drawbacks to this approach:

1. If ONE valve in a group fails to open, or it's endswitch craps out, and valves to the left (in the drawing) of that valve won't open, and the boiler won't fire for that zone.

2. The boiler won't fire until ALL valves in the group open, so there may be a short delay between t'stat call and boiler firing. This is not a big deal... how long does it take those valves to open? 30 seconds maybe? a minute?

A possible 'upside' to point 1 above is that if a single valve in a group fails, it will probably be noticed sooner since the entire zone won't have heat, rather than just one loop which could go unnoticed.

This same sort of idea could also be used with Taco ZVC zone panel... but drawing that will be more difficult.

 

I kind of like this wiring scheme - in series rather than parallel - because it's basically a functional test each time there is a call for heat. This would address one of my concerns which is that I don't have a good way to test the MVAs. But I wonder about using the thin red wires to carry the voltage rather than merely indicate the position of the end switch with continuity. Am I assessing the situation here correctly?

Right now, the system is functioning nicely (upstairs is limping along on just two MVAs since I have lost confidence in the other four. I have removed them AND put the caps on to close those valves. Makes for uneven heat, but I'll have to find a way to test the suspect MVAs (see above) and/or get replacements online since it appears local shops don't sell retail.

The problem now is that I am losing system pressure resulting in the boiler shutting down due to "LOW WATER". Two aspects to this problem: 1) the grey valve doesn't appear to be working automatically since it fails to open to allow new water into the system when the pressure gets below 8 psi or so. I can (and do) manually temporarily set the valve to 25 psi or so which results in the boiler SYSTEM PRESSSURE climbing up to the target of 12 psi. Then I set the grey valve back down to 18 psi which is where I believe it is suppose to be set at. I have to do that every 12 hours or so. 2) the pressure relief valves are passing way too much water. This is where the system is losing water/pressure. I have tried opening the pressure relief valves momentarily to flush them out to see if the problem is that they are failing to seat properly. But that doesn't seem to make any difference. So the big question is why the system is losing water/pressure. Is the pressure really getting so high (above 18 psi I think) that the relief valves (one for domestic water, the other for heat) are opening up as designed? Or are both valves defective - which would mean I have 3 defective valves. That seems pretty unlikely. BTW when there is a demand for hot water, the system pressure jumps up to 30 or so, then falls back down after the cycle is completed. Is that normal? Could that be where the over-pressure condition is coming from? The call for heat doesn't do that so no telling why that relief valve is passing water.

 

Freezing...the drains do poke out the side of the garage to dump on the ground outside. What would I need to do to protect against freezing?