New Boiler not working in Loft

[Timuk]

Can anyone help please

Recently had a new Worcester Greenstar 24RI installed in the loft area. The Boiler loop has been extended to the Loft area and the header tank moved to above the Boiler. 3 way valve and pump remain in the airing cupboard and its an open vented system.

This replaced my 20 year old Potterton boiler which was installed downstairs, and worked perfectly up unit it was replace. With new boiler installation when there is demand for both heating and hot water the radiators don’t come on downstairs, and are luke warm upstairs first thing in the morning. Hot water reaches the Thermostatic valves but the radiator return pipes are cold.

If I turn off the Cylinder Stat off heating comes on. If heating is on and I take a bath radiators go cold until the Cylinder has reached its required temperature. Then the Radiator start to warm up

3 Way valve has been checked and is working OK, pump is OK and Room Stat is OK. Recent replacements.

Plumber seems to think there is a flow imbalance on the return side, with the Cylinder flow return stopping the Heating flow return. He is suggesting that a balance valve is fitted to the Cylinder Return to reduce the flow and balance the cylinder and heating return flows.

My concern is that the reduced flow will not heat the Cylinder up and will not be suitable for the Boiler.

Tim

 

[Puddle]

you should have a balancing valve on the hot water cylinder return anyway ,this is good practice,hot water will still work ok

 

[RoryD]

Symptoms sound confusing (But tats probably me). Could be sludged up following drain down but is a long shot. If you rads are NEVER getting hot then the pump must be suspect. If the water satisfies and THEN the heating comes on your cylinder stat is the fault. They do affect the 3 port valve if faulty

 

[radswilldo]

How many rads are there, its strange that the pipes get hot up to T.R.V's but the doesn't progress furthur, would agree balancing valve should be fitted, but I think something else is going on.

 

[stevetheplumber]

sound like the wiring is wrong if heating comes on when the hot water goes of if it worked before it should work now yes you do need a balance valve on the cylinder but dont think thats the only problem here

 

[radswilldo]

Based on what you say, I keep thinking piping issue, would have to see to say anymore, get engineer back

 

[Timuk]

Many Thanks for all the replies

The 3 way valve has been checked and is working correctly. Sysytem has been power flushed. The flow and return to old boiler in the Kitchen downstairs have been cut below Floor Boards of Airing cuboard and joined on to the new F & R that goes to the new Boiler in the Loft.

What I am thinking now is the location were at were the Cylinder return and the Central heating return meet. This is underneath the floor boards of the airing cuboard. Should this be moved to Boiler level along with the pump?

 

[paul H]

sounds to me that the cylinder circuit has a low resistance compared to the heating and that a valve in the cyl rtn will balance this problem unless there is another problem in the pipe work
regards

 

[RoryD]

Can anyone help please

Recently had a new Worcester Greenstar 24RI installed in the loft area. The Boiler loop has been extended to the Loft area and the header tank moved to above the Boiler. 3 way valve and pump remain in the airing cupboard and its an open vented system.

This replaced my 20 year old Potterton boiler which was installed downstairs, and worked perfectly up unit it was replace. With new boiler installation when there is demand for both heating and hot water the radiators don’t come on downstairs, and are luke warm upstairs first thing in the morning. Hot water reaches the Thermostatic valves but the radiator return pipes are cold.

If I turn off the Cylinder Stat off heating comes on. If heating is on and I take a bath radiators go cold until the Cylinder has reached its required temperature. Then the Radiator start to warm up

3 Way valve has been checked and is working OK, pump is OK and Room Stat is OK. Recent replacements.

Plumber seems to think there is a flow imbalance on the return side, with the Cylinder flow return stopping the Heating flow return. He is suggesting that a balance valve is fitted to the Cylinder Return to reduce the flow and balance the cylinder and heating return flows.

My concern is that the reduced flow will not heat the Cylinder up and will not be suitable for the Boiler.

Tim

On reflection as the other guys have said - u will need a gate valve on the return coming out the cylinder because the water is probably flying around your hot water circuit (least resistance).

 

[Timuk]

Many thanks to you guys for your input. I agreed with Rory the heated water is going through the Cyclinder fast as there is not much Temp difference in boiler flow and return. A will get a valve fitted.

I have another question regarding flow in a 22mm T joint. Currently the Heating Return and Cylinder Return are connected together using a T joint under the Airing cuboard Floor Boards.

This combines the the 2 returns to go to the Boiler return. The 2 returns are connected to the top of the T, to the left and Right and the Flow meets in the middle of the T and then down the centre of the T to the Boiler.

I would of expected the Flow to be through the top of the T from left to Right and from the bottom of the T to the Right of the T. My Question is does this matter??

Tim

 

[RoryD]

seems a bit unclear mate as you're mixing up flow and returns here. There should be only one return and that must be the last 'T' to the boiler on the return

 

[radswilldo]

Your confusing me now, are you actually saying that the return is joined dircectly to the flow, is there a valve (bypass) before they join?. Say no more get a plumber round.

 

[doitmyself]

Currently the Heating Return and Cylinder Return are connected together using a T joint under the Airing cuboard Floor Boards.

This combines the the 2 returns to go to the Boiler return. The 2 returns are connected to the top of the T, to the left and Right and the Flow meets in the middle of the T and then down the centre of the T to the Boiler.

Like this?

From Rads-----T-----From cylinder  
            To boiler

I would of expected the Flow to be through the top of the T from left to Right and from the bottom of the T to the Right of the T.

Like this?

From Rads-----T------To boiler
         From cylinder

The second is better. The reason for this is that the resistance to flow through a T piece is negligible in a straight line but high when it comes to turning the corner. So, when the heating is off, the return from the cylinder will prefer to continue straight on into the radiator return, which could lead to "reverse circulation". The rads could then heat up when not required.

In the second arrangement the flow from the cylinder would meet a higher resistance in the direction of the rads so it will prefer to flow towards the boiler.

 

[Timuk]

hello all

Thankyou DOITMYSELF for understanding my question. The answer you gave was what I suspected. How you connect your T joints is important so the main flow (Heating Return in this case) is across the top of the T.

After all a Cylinder is just another heat output device hanging across the Flow and Returns.