H/W and H/W with C/H together but NO C/H ON IT'S OWN - HELP!

[D_Hailsham]

Wouldn't do any harm to clean out the tank.

Tie up the ball valve

Use a jam jar etc to transfer the water to a bucket. When all the water has gone, use a rag/sponge etc to remove all the gunk lying on the bottom of the tank.

Try to get the tank as clean as possible.

Untie the ball valve.

Is your tank insulated and does it have a lid? If not get a lid and a tank jacket. You will have to cut a hole in the lid for the vent pipe.

Another faint pic!

What is the vertical drop from the water level in the tank to the top of the pump?

 

[Wildeman]

I will give the tank a clean tonight, the tank has a jacket and a lid - albeit a poor fitting one.

The scanner is rubbish as my drawing was really dark, the vertical drop pipe from the F&E tank to the pump is the feed to the system from the tank to top it up.

 

[MANDATE]

I think you'll find he was after a measurement between pump and water level in tank. The greater the drop, the greater the pressure at pump.

 

[Wildeman]

The drop from the water level in the tank to the pump is about 75-80cms

 

[D_Hailsham]

The drop from the water level in the tank to the pump is about 75-80cms

That's a bit on the low side. I can;t find the figures foe Wilo pumps, but they will be comparable to Grundfos who give the folowing info:

Water temp - Min height
75°C - 0.5 metres
90°C - 2.8 metres
110°C - 10.8metres

You will see that the distance does not vary linearly with temperature. The max temperature of your boiler is 82°C. If you plot the data on a graph and get a best fit line you will find that at 82°C the height should be about 1.2 metres.

 

[MANDATE]

Any update on your problem?
I'm still thinking partial blockage. Have you considered a cleaning agent and flushing.
A by pass pipe and valve would help but not guaranteed to cure problem.

Still waiting to see Doitalls response

 

[doitall]

A


Still waiting to see Doitalls response

Remind me