boiler depends on bathroom rad,

[gungaabayar]

hi all
one bedroom flat with 5 rads. Heat only Boiler is in the Kitchen, system has bypass. Two water tanks are in the lofts. Nearest rad to the boiler is in the bathroom.

Problem is:
1. if Bathroom rad's valve is open less than 1 and half turn and pump speed sets to 2 then boiler hardly works.
2. if Bathroom rad's valve is open more than 1 and half turn and pump speed is 2 then boiler works fine. but radiators doesn't get warm equally. seems like all hot water goes to rad in the bathroom and return to boiler apparently.
3. if pump is set to highest speed at 3 then boiler works fine no matter of how much the rad in the bathroom open. (dnt want pump set to highest speed 3 cos all rads are very noisy)

It seems the boiler depends on the the radiator in the bathroom.

Question is why is that?

any advice will be very appreciated,

cheers
DG

 

[stevetheplumber]

sounds like the rad is fitted as a bypass

 

[Unregistered]

sounds like the rad is fitted as a bypass

But there is a dedicated bypass.

 

[townfanjon]

If its a auto bypass is will only open under pressure, so if theres a path through the bathroom rad it will never open.

 

[Unregistered]

If its a auto bypass is will only open under pressure, so if theres a path through the bathroom rad it will never open.

Its not automatic bypass. As far as i know Pipe goes to the bathroom rad is after bypass . Anyways, it's working today. Sometimes boiler dont start. In order to get it working I need to increase of the pump speed , or open the bathroom rad little further.

Rest of 4 rads all open always.

why boiler sometimes dont start depending on the rad in bathroom?

any clues.

 

[Simon F]

are the other radiators open??
as in is the system properly balanced, sounds like it's not.

Is this a recent change, or always been like this?
pump could be on the way out, for 5 radiators speed 1 should be sufficient.
what setting is the hot water tank on, time in relation to radiators?

 

[Unregistered]

are the other radiators open??
as in is the system properly balanced, sounds like it's not.

Is this a recent change, or always been like this?
pump could be on the way out, for 5 radiators speed 1 should be sufficient.
what setting is the hot water tank on, time in relation to radiators?

All rads always open,
no recent change but pump.
Hot water and heating never work same time. There s no lockshield valve in cylinder. It causes bad balance I think. Always have them worked separately. Hot water on its own works very well.
How we use the CH and DHW is whenever we need heating then put heating on for a while and switches off. If we need hot water then put hot water on until the water in cylinder gets hot and switches off. So most of the time they are OFF.

I tried to draw diagram of the heating system and please have a look at it in the following link.
I tried to balance the rads but not sure I did right.

image.jpeg Photo by gungaabayar | Photobucket

So what I have to do get this rads work properly. ?

cheers

 

[townfanjon]

' Close couple 'your vent, feed and pump location, i dont know how to do links etc etc , no doubt somebody will be along shortly

 

[rjvermeulen1972]

All rads always open,
no recent change but pump.
Hot water and heating never work same time. There s no lockshield valve in cylinder. It causes bad balance I think. Always have them worked separately. Hot water on its own works very well.
How we use the CH and DHW is whenever we need heating then put heating on for a while and switches off. If we need hot water then put hot water on until the water in cylinder gets hot and switches off. So most of the time they are OFF.

I tried to draw diagram of the heating system and please have a look at it in the following link.
I tried to balance the rads but not sure I did right.

image.jpeg Photo by gungaabayar | Photobucket

So what I have to do get this rads work properly. ?

cheers

From your drawing the pump is facing the wrong direction? did you say you had work done on the pump?

 

[gungaabayar]

From your drawing the pump is facing the wrong direction? did you say you had work done on the pump?

pump has been changed by plumber. It is right direction. I just drew it on the diagram wrong way. Two zones valve is just after the pump.

 

[ambrosia]

what happens when you leave the heating off and have only the water on
any heat at all going to towel rail


are those zone valves crunching or moving freely

 

[gungaabayar]

what happens when you leave the heating off and have only the water on
any heat at all going to towel rail


are those zone valves crunching or moving freely

hot water is absolutely fine when heating is off and water only goes through hot water zone valve. Rad in bathroom never gets hot in this case.

the other day, heating was working fine , and as I closed rad in bathroom then boiler stops straight away.

 

[Simon F]

so there is a problem with circulation.
possible causes
bad pump, but thats new
balancing issue
sluged system
crusted up 2 port.

I would start with the balancing, the side of the radiator that is used to balance is the lock sheild not the trv.
open valves fully on the radiators furthest from the boiler

 

[gungaabayar]

so there is a problem with circulation.
possible causes
bad pump, but thats new
balancing issue
sluged system
crusted up 2 port.

I would start with the balancing, the side of the radiator that is used to balance is the lock sheild not the trv.
open valves fully on the radiators furthest from the boiler

I know there is definitely balancing issue. I tried to balance it myself using all lockshield valves rather than TRV. Further rad is fully open.

When I moved in this property year ago, it had a problem and a plumber did power flush and put new pump which is Grundfos alpha 2. But not sure system may have still sludges inside I suspect that.

Tonight I did few tests

1. Put heat on with pump speed 2 and bathroom rad is halfway open. Minutes later bathroom rad is very hot and water goes to rest of the rads quite slowly but still getting hots from the top to bottom. The rads' returning pipes are still not hot enough.

2. Then I tried to close bathroom rad slowly and boiler stops working and little screen on the boiler showing C-ish shape. that may mean boiler reaches its temperature. Then I increased pump speed to 3 then boiler started to work again. gradually all rads gets hott-ish but still not warm enough in the rooms.

3. Then I closed bathroom rad fully then boiler still works and rads getting quite hot. The rooms gets quite warm as well. Thats what I want.

4. Then I put pump speed to 1 then boiler stops working. even I opened rad in bathroom fully.

5. put pump speed to 2 then boiler starts working.

I feel the pipe beyond the bypass valve is very hot.

6. Normally boiler temp dial in the front of boiler is set to just after e mode. I tried to put the dial back to e mode then boiler stops showing c-sh shape. If I put it back to just after e mode (increasing temp) boiler start to burn. I was thinking the boiler may need service or not?

I watched and read a lot of plumbing videos and articles to balance the rads (as Im not a plumber) ,It was not may be done properly by me. What I did to balance them was assuming rad in bathroom is nearest and rad in bedroom is furthest. And opened bathroom rad is half turn, then kitchen and lounge ones 1 full turn and , the corridor's rad is opened 1 and a half turn , finally the rad in bedroom is fully open.
It seems work in case boiler works. But the boiler is sometimes not working cos of rad in bathroom.

when boiler is not start it shiows F 2 messages sometimes, it may mean no water flow I think. Definitely water circulation problem there.

so Im gonna start balance the rads again and any advice will help me a lot guys,

Also leaving pump at speed 3 all the time is OK or not? at speed 3 pump working vigorously and all rads have a water flowing noises which I dont want cos pump could be knackered soon.

another thing I noticed today was tried to put only water on with pump speed 1 then boiler failed to start. as soon as pump speed increased to 2 then boiler started.

all these tests could tell you clues whats wrong here,

cheers

 

[ambrosia]

sounds to me like theres a pipework issue and youre going to end up re doing the flow pipe surrounding that rad because currently that rad is part of the flow

 

[gungaabayar]

sounds to me like theres a pipework issue and youre going to end up re doing the flow pipe surrounding that rad because currently that rad is part of the flow

It cant be part of flow cos CH works fine with pump speed 3 even the rad is complitely closed

 

[Unregistered]

It cant be part of flow cos CH works fine with pump speed 3 even the rad is complitely closed

The fact that the boiler operates only on pump speed 3 when bathroom radiator is fully shut shoes that there are issues with your pipe work. Whether it's sludge or the way it is plumbed in will only become clear after investigation. water will always take the easiest route.

 

[gungaabayar]

The fact that the boiler operates only on pump speed 3 when bathroom radiator is fully shut shoes that there are issues with your pipe work. Whether it's sludge or the way it is plumbed in will only become clear after investigation. water will always take the easiest route.

Boiler works fine on pump speed 3 no matter bathroom rad closed or not. Also Boiler do work on pump speed 2 when bathroom rad more than 2 turns open but it steals hot water.

anyways I played little bit today with the issues,
Put only hot water ON then water goes through hot water zone valve and in a minutes bypass valve opens why I know is I felt hot water in the pipe after bypass valve. And the pipe gets hot until it reaches the tee through which this pipe connects to main return pipe. I realised the return pipe dont get hot beyond the tee. seems like the tee is blocked by sludge. I knocked the tee few times with screwdriver handle and suddenly the main return pipe gets hot. Switched hot water off and Put heating only ON with pump speed 2. system work. Closed bathroom rad and boiler still works. happy moment. after for a while opened the rad quarter of turn, of course still fine. Seems like little blockage at the end of the pipe after bypass valve caused the problem making bathroom rad as bypass. When pump speed higher (at 3) strong water flow gets through the little blockage I think but not sure. A magna clean is a meter away from the tee , hopefully it gets the little :nono: which blocked the tee from bypass side, I will check it soon and let you guys know. I will see and keep an eyes on it.

also when I put only hot water ON, I felt hot water in the pipe beyond heating zone valve. but it dont go too far, it tells me heating zone valve left little open. Is it normal or it must be fully shut during hot water only ON

cheers