MegaFlo Hot Water Flow Problems After 60 Secs of Running

[justinaperry]

Hi eveyone I'm in a real pickle and needs some advice.. the ear ache I'm getting from the wife is killing me.

I have a three story property with a MegaFlo unvented hot water system with expansion vessil and all those clever bits and pieces. I have some really anoying intermittent problems with water pressure and flow.

At some points the hot flow drops to zero (nothing out of the tap) after just a few seconds of the hot water running fine at high flow and good pressure. I have tried re-energising a few times and it sometimes helps the problem however it is not a permanent fix and currently we get around 60 seconds of good flow and pressure before dropping to almost zero.

I am wondering if there is a blockage in a filter or something that could be preventing the pressure remaining high once the hot tap is in use, but I'm only a DIY plumber and don't really have any experiance with this sort of system. It seems to take a while to build the pressure back up and we have the same problem all over again. We get some real funny noises from the airing cupboard when using cold water in the house - does this mean anything?

 

[justinaperry]

I have found some details regarding the strainer mesh in the cold water combination valve. Could this be the problem?

I can't see how I remove it - has anyone got any ideas it isn't clear.

8.3 CLEAN THE STRAINER
The strainer is incorporated within the Pressure Reducing Valve housing of the Cold Water Combination Valve (see Figure 2). To inspect and clean the strainer:
i) Turn off the isolating valve on the Cold Water Combination Valve by turning the black handle so it lies 90o to the direction of flow.
ii) Open the lowest hot tap in the system to relieve the system pressure.
iii) Using a spanner unscrew the pressure reducing cartridge and remove the moulded housing. The strainer will be removed with the cartridge.
iv) Wash any particulate matter from the strainer under clean running water.
v) Replace the strainer and screw the Pressure Reducing Valve cartridge into the moulded housing.
vi) Close hot tap, turn on isolating valve by turning handle so it lies parallel to the direction of flow. Check for leaks

 

[oilman]

ii) Using a spanner unscrew the pressure reducing cartridge and remove the moulded housing. The strainer will be removed with the cartridge.

If anyone has managed to do this on anything other tahn a new unit, in a hard water area I would be interested to know.

Have you regenerated the air bubble?

 

[justinaperry]

Yes I have regenerated the air bubble a few times.

 

[dkleeman]

I may be being thick, but I can't see how to remove the cartridge with a spanner. There are four allen keys on top of the valve and no sign of a nut below. I removed the allen bolts but the cartridge did not come off easily and I did not dare to pull hard.

 

[Boilerman2]

You have done right in removing the allen screws, the cartridge should prise out a screwdriver blade to separate the two halves may help?

 

[dkleeman]

And water does not come pouring out / my house does not blow up??

 

[Boilerman2]

not as long as you have turned off the water on the black lever and depressurised by opening a lower hot tap (I always have an OLD bathtowel handy to catch any odd water that may run out

 

[petit_pablo]

And water does not come pouring out / my house does not blow up??

I presume you drained the water first?

More often thn not the strainer won't come out and the body separates rendering it useless

 

[dkleeman]

Thanks for the advice everyone. The cartridge came out and the strainer did not disintegrate. There was a fair bit of crud in the strainer but probably not enough to affect the overall flow.

Daniel