Motor valves banging

muckwarrior

Have just had a three zone heating system installed and there's a fairly loud bang when the heating turns on or off. It always seems to happen when it turns off and sometimes when it turns on. I've read a few threads that suggest that installing the valve backwards will cause this. I took a look today and I *think* they're installed the right direction, but wanted to check. See attached photo with the direction of the valve arrows indicated.

Before you say ask the plumber who installed it, unfortunately I seemed to have hired a bit of a cowboy, who did his best to fob me off with the rest of the snag list items, hence I'd rather go to him with what he needs to do rather than asking him what's wrong.

10-10-20

What brand of valves are those (in yellow)?

muckwarrior

https://www.boards.ie/discussion/comment/119723456#Comment_119723456

This, I think https://www.screwfix.ie/p/eph-controls-v221p-2-port-motorized-valve-compression/227hp

John.G

If they are on the boiler flow pipe then correct, if on the return to the boiler, then incorrect.

Are these three valves on the heating? or is one for DHW (assuming not a combi boiler) and if so does this bang as well?.

Bazmo

Had this exact issue Mentioned it to boiler service chap who stated that it was a motorised valve installed incorrectly.

Got the chap who had installed the valve back out to switch it around and that solved the problem.

muckwarrior

https://www.boards.ie/discussion/comment/119723866#Comment_119723866

I assumed they were on the flow, but now that you mention it, I need to confirm that. I guess the easiest way is turn it on and see which one heats up first?

Yeah, one (on the right) is for hot water. I haven't checked yet whether or not it makes a noise. Not living in the house yet and have only had time for a brief check.

John.G

If thet are installed correctly, suggest looking at at boiler pump settings as a very high (100%) pump setting is probably ~ 7M. so maybe reduce this to its minimum of I read somewhere to 70% which = 3.43M head.

Doolittle51

That pipework is comical, so many unnecessary bends and elbows.

I can't see any bypass route. The boiler pump will continue running for a few minutes after all heating zones are turned off, to dissipate heat from the boiler.

If all 3 valves close as soon as the timer is turned off, then it looks like the boiler pump will dead head.

youtheman

https://www.boards.ie/discussion/comment/119723896#Comment_119723896

Those 3 valves are on the same pipe from the boiler. So if one is wrong they are all wrong.

https://www.boards.ie/discussion/comment/119724413#Comment_119724413

This is what I thought of. If there is no bypass then when the boiler reaches the set point and the valve(s) close then the pump dead heads. This is what I would look into first.

muckwarrior

Am I right in thinking that a "bypass route" would involve a pipe between the feed and return pipes (e.g. green in pic) with an automatic bypass valve on it?

Doolittle51

Yes it needs to go between the flow and return, just not sure if that loop would be big enough. It would prevent dead heading, but with such a short loop, it might take ages to dissipate the heat.

youtheman

Check that the bypass valve is not fitted within the boiler casing. In my house I have a Vokera Gas Boiler and it is internal to the boiler casing. In my Mother's house it is a Grant Oil boiler, and it is external to the boiler casing.

John.G

Quite alot of gas boilers have a internal one, as above, and most manufacturers say that this is OK as long as the boiler isnt cycling for prolonged periods, in which case, a external one is required, (otherwise it would stay off for far too long before refiring).

However, there are thousands of oil fired boilers, like my own that have no form of bypass whatsoever and the valves don't bang.

Doolittle51

Have a look at the manual for Ideal boilers.

It says that a bypass valve should be fitted unless you have a radiator with twin lockshield valves to act as a bypass. In your case OP, this isn't possible because all your zone valves are in parallel on the boiler flow.

muckwarrior

https://www.boards.ie/discussion/comment/119726695#Comment_119726695

I just checked and it actually also mentions 2 port valves "However, if the system employs thermostatic radiator valves on all radiators, or two port valves, then a bypass circuit must be fitted with an automatic bypass valve to ensure a flow of water should all valves be in the closed position."

Thank you for the irrefutable proof!

John.G

Presume you now have irrefutable proof that the valves are installed on the boiler flow?. If so you could carry out a crude test sometime by getting the boiler to call for DHW then get one of the heating zone valves to open/close and see if the banging has stopped. If so suggest setting the pump speed to its minimum which I think on the Logic is 70% so if its a 8M head pump it will now run at 3.92M head or at 3.43M if a 7M pump which may stop the banging until a (if) ABV is installed.

muckwarrior

Just had time for a quick check tonight.

The motor valves are installed on the flow. There is no evidence of a bypass circuit. I checked turning on heating with and without hot water on. Interestingly there's still an audible thump when turning off the heat, but it's significantly less when the water is on.

I didn't get a chance yet to find out how to view/change the pump speed .

John.G

Still somrthing not quite right there IMO, the boiler default pump speed is 70%, around 3.5M, so unless your installer bumped this up to 100%, there should be no valve thumping, even with a ABV installed which will be set to slightly lower than 3.5M which still may not cure the problem.

To be sure, to be sure, have one more look at those valve bodies, the flow (& arrow) should be from port A to port B, with A on the bottom of the two top valves and on the top of the bottom valve?.

muckwarrior

Holy ****, you're right! I just double checked the photos I took of the valves and realised that I'd gotten the upstairs and downstairs mixed up. Both of those are installed pointing towards the flow. The HW is the only correct one.

Doolittle51

Just looking at the picture of your pipe work again, it does look likely that the 2 valves on the left are installed the wrong way around. As can be seen in the picture above, the direction of flow is towards the cable connection on the actuator.

Edit: Already confirmed by OP!

John.G

It could happen to a Bishop.

Doolittle51

If that solves the problem, I think a bypass should be fitted anyway.

I'd be concerned that the boiler warranty might not be valid if the system installation isn't as per the boiler manufacturer's recommendation.

witnessmenow

https://www.boards.ie/discussion/comment/119729875#Comment_119729875

Sorry to hijack but we got a similar type of system setup recently on our house, but we only did the two rads (upstairs and downstairs). HW is unobstructed (so not switchable). I believe the advice the plumber gave at the time is this would not be a problem to have even both rads closed as the HW still completed the loop (and everything is working fine so far), is there still need for a bypass in this type of scenario?

John.G

So the HW has no te.perature control so no motorised valve ? Is it programmable to be on even if CH is not required?

Or is it just a loop and onlyy heats the cylinder when CH is called for??, if so then it acts as a permanent bypass

witnessmenow

https://www.boards.ie/discussion/comment/119729959#Comment_119729959

We have a kind of DIY system, we have 3 separate Wifi relays (sonoff Mini), 1 for controlling the CH (and pump) and then one for each motorised valve (upstairs and downstairs).

Yeah I believe its your second option. The water gets heated when the CH is turned on, regardless of the state of the motorised valves. So if we want only hot water, we close the valves and turn on the CH. If we want to heat the upstairs rads, we close the bottom , open the top and turn on the CH, but this will also heat the water.

John.G

Yes, "bypass" loop open at all times, not a very economical way of heating the cylinder as the cylinder will be heated to the boiler flow temp which may be as high as 70/75C but if set to 60/65C then probably not a huge extra cost in fuel, if any.

witnessmenow

Thanks @John.G . Is the best long term approach to get a motorised valve for the HW and get a bypass installed? Probably wont be doing it anytime soon but would be good to know!

John.G

Yes, that's the best way.