Hot water but no central heating Ideal Logic 24

[cheltenham08]

Ideal Logic 24 boiler.


There are 3 circuits, hot water, under floor heating, radiators.


When the hot water calls for heat the boiler fires up fine and water heats up. When either or both of the central heating systems calls for heat the boiler errors with error code Fd, no water flow.


When the boiler is heating up for the hot water and either of the central heating systems is on, then water is pumped to them fine, the radiators and / or underfloor heating warms up.


The water flow sensor was replaced only 3 months ago when we had the reverse problem. Heating but no hot water. We have not tried using the central heating since then.


The person who came and replaced the water flow sensor has been to have a look but is at a loss as to what the problem is. He has spoken to Ideal who are saying it is not a boiler problem.


It is now being suggested we have a complete system flush, but I can't see how this will help if the water is circulating round the central heating system without a problem.


Any thoughts on where we should go from here?

 

[nysk2008]

I can't see how this will help if the water is circulating round the central heating system without a problem.

How do you know this?

 

[SimonG]

Could be an issue with the controls external to the boiler.

So just to confirm, you can have radiators and underfloor heating going at the same time as the hot water and it all heats up, but when you try underfloor or radiators separately then the boiler cuts out.

Any pictures of the valves and controls?

 

[cheltenham08]

That's what I thought .......

The radiators get hot and the pipes to the underfloor heating warm up when the how water is calling for heat and either of the central heating circuits is also on. We have managed to get about half an hour of heating morning and evening!

 

[nysk2008]

sound like circulation issue to me?

 

[cheltenham08]

Could be an issue with the controls external to the boiler.

So just to confirm, you can have radiators and underfloor heating going at the same time as the hot water and it all heats up, but when you try underfloor or radiators separately then the boiler cuts out.

Any pictures of the valves and controls?

Yep that is correct. With everything off and then just activating either of the heating circuits the boiler will not fire up. Error code Fd no water flow.

Picture below:

 

[cheltenham08]

sound like circulation issue to me?

The pump for the radiator / hot water circuits was replaced only 3 months ago. Water is circulating around the central heating system as the radiators are heating up.

Could the flow sensor have been wired incorrectly when it was replaced in June?

 

[Ermintrude]

Possibly valves not wired up correctly. U need a GSR . Zv probs not wired correctly. Pump probs wired on to dhw demand and not other zv. Pump should be direct connection to logic heat only! Installer not competent with electrics? Flow switch probably ok but issue is with setup. Turn boiler off, put on boiler without any hot water or heating being called for and I bet pump doesn't spin...... Not connected up correctly and or flow and return back to front.

 

[cheltenham08]

Possibly valves not wired up correctly. U need a GSR . Zv probs not wired correctly. Pump probs wired on to dhw demand and not other zv. Pump should be direct connection to logic heat only! Installer not competent with electrics? Flow switch probably ok but issue is with setup. Turn boiler off, put on boiler without any hot water or heating being called for and I bet pump doesn't spin...... Not connected up correctly and or flow and return back to front.

Since installation in 2011 by GSR engineer everything worked fine. Then we had problem when in June this year we turned off the central heating and the boiler would not fire up to give us hot water.

A GSR engineer came and replaced flow sensor and one of the pumps and we had hot water.

Now switch on central heating and we have no central heating but we do still have hot water.

System worked OK for 2 and half years.

 

[Ermintrude]

Sorry assumed new fix. Probs zv contact or when replacing pump made a mistake? Pump should still be wired direct to boiler . Where are u? Some one from forum probably help u.