Hot radiator

[PCAnimal]

Hi,
I have a problem and I'm looking to diagnosis it. The heating has been off due the funny thing in the sky.
When i have a shower the radiator (closet to tank and no thermostat fitted) in the bathroom becomes hot like the heating is on. Ive also had to top up the ch system which has gone to zero bar twice in one week. The system has been up and running for months without issue.

I've heard it could be a 3 way valve sticking. Im just wondering how to solve it

Setup
I've got a worchester bosch greenstar 18ri,
An unvented hot water tank


Thank you

 

[heatservice]

Your system could be designed that way as it just the bathroom rad getting hot, if your 3 port valve is letting by you could check to see if the heating pipework is getting hot a few feet away from the valve when you know your boiler is operating to heat just the water, I would think your loss of system pressure is unrelated so check for leaks inc the PRV warning pipe which can often be found sticking out the wall behind the boiler if your boiler is fitted on an outside wall.

 

[BWC]

As heatservice said , the bathroom radiator could be what is referred to as a heatleak radiator , this means this radiator will have been connected before the 3 port valve , this was common on older systems to act as a bypass and a way of drying / warming towels even in summer months, personally I see no problem in getting a thermostatic valve fitted if this is the case as your system does not require a bypass. (Y plan) as your hot water cylinder coil will act as a bypass.

To prove that the 3 port valve is not passing , follow heatservice before advice .

Cheers

 

[PCAnimal]

Ok cheers its odd that we have only just noticed it. Prev it went on with heating.
The 3 way port is in our airing cupboard and the radiator which gets hot is in the loft. That radiator is higher than the valve.

 

[BWC]

Have you checked that when the hot water is on by itself that the pipe exiting the 3 port valve to feed the rads is or isn’t getting warm ?

 

[PCAnimal]

I will have a look at that. So can i turn off heating with just hot water on. Use some water and see what it does.

 

[heatservice]

Ok cheers its odd that we have only just noticed it. Prev it went on with heating.
The 3 way port is in our airing cupboard and the radiator which gets hot is in the loft. That radiator is higher than the valve.

Is there a pipe tee'd out of the flow pipe between the pump and 3 port valve, if so I would think its supplying that radiator which would therefore get hot when heating or HW were called for.

 

[BWC]

I will have a look at that. So can i turn off heating with just hot water on. Use some water and see what it does.

Yes that’s correct , check and confirm that when the boiler fires for water only

 

[PCAnimal]

Hi,
I've attached a photo. A plumber came around before Christmas and fitted what he called a safety bypass valve. I think he said it was to stop trapped hot water.
I've just run the bath for 5 mins then stopped. When the HW came on it came up to the bottom of the 3 way value. It then went to the right and up into the loft. However before the 3 way is a T which looks like it feeds the CH system. This got hot and then went up to feed the bathroom radiator.

I didn't want this. I would like the CH on when I want it on and not when I draw hot water. It seems a bit of a waste especially in the summer. Does this seem correctly plumbed?

 

[BWC]

As heatservice suggested then, I wouldn’t say it’s incorrect strictly speaking, I would of asked my customer if they would like it done that way personally before doing it that way myself. Maybe the plumber done this to create a system bypass which again technically it is not a requirement so I wouldn’t blame the plumber if you see what I mean. Easiest way to allow you to stop this rad heating during water only (summer time) would be to fit a Thermostic radiator valve on the bathroom radiator and as it’s in the loft very little water will need to be drained from the System , a plumber should charge around 50 - 75 pounds approx to do this , in the meantime you could close one side of the radiator down to prevent unwanted circulation at one of the valves. Or alter the pipework so it tees off after the 3 port valve ...

 

[BWC]

Plumbing does look a right mess though and it’s hard to tell what’s what from that picture but in short if the rad is heating when only hot water is selected and the valve is not letting by then it has either been piped to come on with either heating or hot water or the return from the rad has been placed after the cylinder return (reverse circulation)

 

[ajstoneservices]

Wind the black knob in a clockwise direction until the flow stops through the valve with the hot water cylinder being heated.

 

[PCAnimal]

I've added a couple more photos. What is that black thing called? He said something about it be a safety bypass. It looks like it can be turned to adjust things. Would adjusting this make any difference?

I can drain it down and fit a thermostatic valve. I am just not sure what this bit is all about. I assume everything to the left would normally be CH. It is odd why he would bypass it. Its even stranger that it goes into my magnaclean.

 

[heatservice]

I totally agree with BWC, have a TRV fitted to that rad and turn it to a low setting during the summer, some people love to be able to warm their towels even in summer but your plumber should have discussed the pros and cons with you before going ahead.

 

[BWC]

I agree heatservice, op the bypass won’t cause the rad to heat up , so adjusting it will do nothing atall , the bypass creates a path back to the boiler in the event the valve closed down , impossible on your system as always has a open route, the plumber may of done this to prevent noise in the system ...