Unvented system, shower losing pressure when other tap used or toilet flushed

[cat_tay]

We moved into a 2 bed property 3 months ago, we had the heating replaced with an unvented system. The water pressure is good in all taps, the plumbers said that they increased the size of the pipe coming into the house to increase it further.

We had a new bathroom installed and now when the shower is on, the pressure is fine unless someone turns a tap on or flushes the toilet and then the pressure drops right off.

The plumbers have said they think it could be an issue with the pipes coming into the house and to contact our water provider. Not sure if this is correct as the pressure coming into the house (i.e. in the taps is really quite good). They have installed a big water tank as we plan on extending so that it can cope with the extension, but it seems pointless in having another bathroom if the water can't even cope with a shower and a tap being on, let alone 2 showers!!

Any advise please???

 

[gassafe]

I would check the shower is plumbed off the systems hot & cold balanced supply pipes.

What unvented system do you have? Was it installed by a G3 registered person?

 

[Unregistered]

It's a 30kw Glowworm sealed system boiler with 210 litre pressurised hot water cylinder. What is G3? they are corgi & oftec registered & also with the gas safe register.

 

[walterwhite]

G3 relates to the building regs. You should have received notification certificates for both the boiler and unvented cylinder. It's illegal to install an unvented cylinder without the g3 ticket & not all gas safe engineers have the ticket. Bit late now to see if they were qualified to install it. However, before recommending an unvented cylinder the incoming main needs to be checked for pressure and flow. If it's less than 2 bar & 20 litres a minute then they should have told you before that the incoming main would need to be upgraded.

 

[walterwhite]

Also, 2 bed property with a 30kw boiler! I think you've employed some muppets. (Sorry)

 

[cat_tay]

I've checked and we have got the certificates, so they are qualified. The boiler is 30w for when the house is extended. The did test the water pressure before it was installed and also widened the pipes coming into the property.

The water pressure issues - do you think this is due to an issue with the plumbing / sealed system or could it be the pipes belonging to the water company that are 'furred' up?? I'm not sure if they're fobbing us off rather than fixing something that is down to them.

Thanks

 

[townfanjon]

Does the pressure drop off at all other hot outlets as well as the shower , if not its probably the shower at fault

 

[cat_tay]

Just checked with the kitchen tap, it isn't affected by the toilet (also downstairs as bathroom one not plumbed in yet!), but the upstairs basin tap is affected by the downstairs toilet being flushed!!

 

[cat_tay]

It was the hot taps that were checked.

 

[macackau]

Do you mean pressure drops or flow rate drops? Have you got an outside tap that you can check your water flow rate at? Need to know how many litres a minute your house is getting. Get a measuring jug and time how long it take to fill a litre to calculate it. I think the issue is you haven't got at least 20 litres a minute in the property.

 

[cat_tay]

I'll check the outside tap in the morning. Thanks all for your replies

 

[SimonG]

Could be debris in the strainer or a faulty pressure reducing valve. Needs somebody with g3 to investigate.

So when they widened the pipe coming in what size blue alkathene did they install and how deep? Or was it just increasing the 15mm rising main to 22mm before it fed the cylinder?