Bypass gate valve help

[76487632]

Hi,

My central heating has been bad for many years now (several radiators not heating up) and I've only just found that the gate valve in the bypass circuit is fully open - water can flow around through the pump and back to the boiler without going through any radiators.

Shutting the valve completely means all the radiators heat up in seconds.

However due to the way it's been set up, when only the hot water is on (and heating is off) it has to flow through this bypass valve to return to the boiler. So it needs to be open.

What is the best practice for setting the amount this valve is open? Should it actually be fully open or do I need to find a balance?

I also see you can get automatic valves. Would it be beneficial to get one?

This is a regular boiler system around 20 years old.

 

[Keefy]

Close your gate valve all the way then give it a quarter to one full turn back then see how your rads respond. In the meantime try to get some pictures uploaded of the bypass including the surrounding pipework.

 

[76487632]

Close your gate valve all the way then give it a quarter to one full turn back then see how your rads respond. In the meantime try to get some pictures uploaded of the bypass including the surrounding pipework.

Thanks very much for the help.

The picture here shows some of the pipework.

The water flows down from the pump.

The bypass is the lowest one on the vertical pipe. The motor valve on the right goes to the radiators. There is another motor valve above all this that goes into the tank coil.
I havent a clue what the pipes do below the bypass but one must go back to the boiler.

 

[76487632]

Wider view

 

[Keefy]

Sorry mate, I've had a few pints and can't make sense of what you're saying. Not saying it's you but a few more wider shots of the whole cylinder and pipework would help greatly... hic!

 

[Chuck]

I also see you can get automatic valves. Would it be beneficial to get one?

Yes. Get someone competent to service your heating and fit it for you at the same time.

 

[sammathias]

Looking by the pictures its all plumbed correctly... You can turn that bypass to almost the closed position which will sort your radiator issues... The hot water should return from your coil when you have the hot water on without the need to go throught that bypass..

 

[doitmyself]

However due to the way it's been set up, when only the hot water is on (and heating is off) it has to flow through this bypass valve to return to the boiler. So it needs to be open.

That can't be correct! It just doesn't make sense.

View attachment 32418

1. Do the two pipes at the back of the cupboard both connect to the cylinder?
2. Does the invisible pipe behind the lower motorized valve disappear into the floor?

 

[76487632]

That can't be correct! It just doesn't make sense.

View attachment 32418

1. Do the two pipes at the back of the cupboard both connect to the cylinder?
2. Does the invisible pipe behind the lower motorized valve disappear into the floor?

No only the bottom pipe goes into the cylinder. There is another one higher up that can be seen in the pic below.

Yes the lower motorised valve has a pipe going down into the floor to the radiators.

Obviously if that lower heating motor valve is closed, the water must go through the bypass valve if only hot water is on.


The pipes highlighted yellow are the cylinder coil pipes. The pipe with a push fit thing is for a towel radiator.

 

[sammathias]

If them pipes you have highlighted are flow and returns to the cylinder then it is indeed piped wrong...you sure they both go into the cylinder?

 

[sammathias]

Surely the lowest pipe running almost along the floorboard is your return from the cylinder?

 

[76487632]

Surely the lowest pipe running almost along the floorboard is your return from the cylinder?

I've double checked and the indicated yellow pipes are definitely the cylinder coil connections.

The big dusty one going along the floorboard is the return to the boiler but I'm not sure why it goes around the tank. It goes into the floor just near the lower motor valve and also goes somewhere behind the tank but I don't think it's connected to the cylinder.

If the central heating is off, and I turn only the hot water on, the pump makes a loud noise if I close the bypass valve - there is no flow.

So if the bypass is fully closed, the hot water doesn't work. If I open it too much, the heating doesn't work well. If it's only slightly open the boiler makes boiling noises and seems to be overheating when only hot water is on.

 

[doitmyself]

Whoever installed that pipework didn't know what he was doing.

I think it's time to ask a heating engineer to come in, check over your system, and correct any errors in the pipework. After Christmas - unfortunately!

In the meantime, open the bypass valve just enough to prevent any noise when HW only is running. Half to one turn should be enough.

Apart from correcting the piping errors, the engineer should replace the bypass gate valve with an Automatic Bypass valve (required by Building Regulations) and adjust it.

 

[jam1979]

That definitely looks like it's piped up wrong I think if the 2 port to the cylinder is moved thurther along and the bypass goes from just before that straight in to the 1 that drops through the floor hence that being the return and the middle pipe having a straight piece put in will probably solve the issue