Logic Combi 30 Low DHW Flow Rate

[pinyinbob]

I have just moved into a property that has an Ideal Logic Combi 30 boiler - installed about two years ago.
The DHW flow rate is pitiful - 3 l/min. (Cold from mains is 12 l/min)
I've tried setting it to a lower temperature but this doesn't affect the flow rate, only the temperature.
We live in a hard water area and there is a 15mm Fernox Fry Electrolytic Scale Reducer fitted.
Is the scale reducer the cause of my low flow and, if so, what can I do to improve the flow?
It takes forever to fill a bath and we like a powerful shower.

Thanks in anticipation.

 

[Scott_D]

Is it the same at all taps
Is the cold water valve into the boiler fully open?

 

[pinyinbob]

Hi! Scott d,
Valve is fully open and it's the same at all taps.
I've just noticed what I think is a non-return valve just after the stopcock.
Could this be the source of my problem?
Suppliers of the scale reducer assure me that it does not restrict the flow.
(So how does it work?)!!!!!

Bob

PS I tried to send a photo but it wouldn't let me.
It must be possible as I've seen others do it!

 

[stevetheplumber]

its a case of working back through the circuit to find the restriction there may be a blocked filter or a valve half of

 

[pinyinbob]

Thanks, Steve,
I am replying to these comments but because I'm new all my comments have to be moderated and it seems the moderators are very busy!!

I've found a non-return valve.
Could this be my problem?

Bob

 

[Scott_D]

It's unlikely as that would also restrict the water to the cold taps

 

[pinyinbob]

Thanks, Steve,
The NRV is just before the boiler on the inlet right after a stopcock so won't affect the cold.
However your comment seems to suggest it will restrict the flow.
Can I remove it or will that transgress some ancient local water bye-law?

Bob

 

[jtsplumbing]

Is cold water tap under boiler fully open ?

 

[pinyinbob]

Thanks for responding, jtsplumbing.
Yes, it's fully open - see posts #2 & #3.
The stopcock before the NRV is also fully open.
The boiler supply is taken from the same pipe that supplies the kitchen sink cold tap.
This tap delivers 12 l/min so I'm back to the NRV.
I've taken photos but can't upload them despite resizing.

 

[jtsplumbing]

So I take it this non return valve is fitted after the connection to the sink ! and is only on the supply pipe to the boiler ?

 

[stevetheplumber]

Yes you will feel the full force of the water company if you take it of and smash the middle out with a screwdriver and hammer you may also find you boiler lights up every time some one opens a cold tap or flushes the loo but it would prove if this was the obstruction

 

[FD Powerflow]

May well need descaling by a GSR engineer. Scale can build up on plate heat exchanger which can restrict the flow and indeed the heat transfer.

 

[pinyinbob]

Thanks to everyone for taking the time to offer assistance.
The boiler is only a couple of years old and has had a scale reducer fitted from new.
There was only one person living here before us so I doubt very much that scale build up is the problem.
jtsplumbing is correct about the location of the NRV.
I plan to remove this temporarily to see if that solves the problem.
Watch this space!!!

 

[pinyinbob]

Problem solved!
I removed the internals from the NRV.
It came apart easily using circlip pliers.
Thanks for the suggestion to "smash the middle out with a screwdriver and hammer" from Stevetheplumber but this was not necessary.
Incidentally, I did feel the "full force of the water authority" after doing this.
They turned up on my doorstep the next day demanding I reinstate it and threatening a fine of up to £1500 and/or up to 12 years in prison. (How did they find out? Perhaps they subscribe to this forum?).

The NRV wasn't the cause in the end anyway.

I downloaded the service manual and discovered a filter and flow regulator are fitted internally.
It was a very easy procedure to remove the DHW flow turbine cartridge, unscrew the flow regulator housing, remove the filter and flow regulator and clean them.
The flow regulator was choked with scale particles.

Hey presto! Lots of lovely hot water.

I hope this can help someone else.

 

[pinyinbob]

Re: Logic Combi 30 Low DHW Flow Rate - Solved!!

All sorted.
It was an internal blockage at the DHW flow turbine cartridge.
The flow regulator was choked with scale particles.
Downloaded the service manual for free and followed the instructions.
Piece of cake.

Hope this helps somebody else.

 

[PhoenixServices]

You being serious about the water board? Plus anyone else think manufacturers,should only allow people with gs numbers to download install/service manuals.

 

[newcastle phill]

Not particularly because most of the MIs have the benchmark in the rear what, at some point they have to have access to anyway...

 

[FD Powerflow]

Thanks to everyone for taking the time to offer assistance.
The boiler is only a couple of years old and has had a scale reducer fitted from new.
There was only one person living here before us so I doubt very much that scale build up is the problem.
jtsplumbing is correct about the location of the NRV.
I plan to remove this temporarily to see if that solves the problem.
Watch this space!!!

So my original post suggesting the issue may be caused by scale and to get a GSR to descale would have solved the problem...