Ideas for low pressure combi

[tjhooker]

Hi

I've just bought an end of terraced house. circ 1900. The water pressure is low.
We have shared mains water. The pressure was measured at 5ltr / min @ no bar taken at 18:00 mid-week by British Gas, then again a few days later 9ltr / min @ 0.7 bar by the water supplier.

There is no water tank. In the kitchen there is an old Glowworm Swift flow combi. Its bar reading is 1.2bar.

We lose pressure and hot water in the kitchen and bathroom when running a hot tap and flushing at the same time.

I want to replace the old boiler and put a shower in. What can I do to increase pressure?

Should I get a dedicated mains supply?

OR

Is there a combi that works at low pressure?

What shower will work with out a pump and still deliver good pressure?

Currently the flue end is 720mm from a third party wall. (Total distance wall to wall is 920mm) Is that sufficient distance for a new combi boiler?

Thanks for any help, suggestions or ideas of cost.

 

[chrishutt]

If you have a shared mains supply, you may find that the water company will separate the supply externally free of charge. You (and your neighbour?) would have to arrange the separation of the supply internally and up to the boundary. Whoever gets the new supply from the main will get a much better flow rate. Worth looking into anyway.

 

[ChrisR]

That water pressure is very poor though. It's right at the level where you could complain to OFWAT. Get a pressure guage (£11 or so) and keep an eye on it, with flow OFF - though your neighbour may have his tap on of course. The pressure must have got to 1.2 bar at some time or other to have filled the combi up to that pressure.

1.2 bar is just reasonable but it probably dips a lot at showering time. Big separate mains pipes would obviously help.
without that the only way you're going to get a decent flow/shower is with stored water - which is something you don't have now so would involve cost and space.

 

[tjhooker]

If you have a shared mains supply, you may find that the water company will separate the supply externally free of charge. You (and your neighbour?) would have to arrange the separation of the supply internally and up to the boundary. Whoever gets the new supply from the main will get a much better flow rate. Worth looking into anyway.

Yes, I thought the same too, but they were very cagey and said as far as they were concerned the pressure was "adequate". They would connect us back up for free but the cost of separation and running a dedicated pipe from the mains to our property would be down to me. The water Co. chap who came out said something about "moleing" (not sure if it's spelt that way). and reasonable costs bt wouldn't give an estimate!

 

[ChrisR]

Speak to OFWAT and get a gauge. But if your pressure with no flow is down to about 1 bar, big pipes won't help much.

 

[tjhooker]

Speak to OFWAT and get a gauge. But if your pressure with no flow is down to about 1 bar, big pipes won't help much.

Thanks I'll get on to them this afternoon.

Can you advise on the distances of new boiler flue and third party walls? I was told it was 600 - 800mm

 

[tjhooker]

UPDATE:

The Water Co. inspector has now said that from the external stop-cock his water reading was 10ltr /min at 5bar. Inside the property the pressure readings are the poor readings above.

According to OFwat: "You do have the right to a separate water supply, but you would be responsible for the cost of separating and replacing pipes"

Looks like I need a professional to separate and replace new pipes to get around this problem. Geez..sounds expensive.

 

[kevplumb]

The Water Co. inspector has now said that from the external stop-cock his water reading was 10ltr /min at 5bar. Inside the property the pressure readings are the poor readings above.

pressure should be the same regardless

 

[chrishutt]

The Water Co. inspector has now said that from the external stop-cock his water reading was 10ltr /min at 5bar

How can there be 5 bar available at the boundary stop tap, but less than 1 bar internally? There would be times of no or little flow when 5 bar would be recorded internally.

As ChrisR says, get yourself a pressure gauge with suitable fittings to connect to your cold supply (e.g. via 3/4" thread washing machine valve) and monitor the pressure under varying circumstances. It does sound as if the water company might be trying to wriggle out of their obligations.

With separate supplies, of course you would have to pay for the work within your property, but check with Ofwat whether the water company have any obligation to provide the separate supply to your boundary free of charge.

 

[tjhooker]

As ChrisR says, get yourself a pressure gauge with suitable fittings to connect to your cold supply (e.g. via 3/4" thread washing machine valve) and monitor the pressure under varying circumstances. It does sound as if the water company might be trying to wriggle out of their obligations.

Pressure guage it is then, with a suitable fitting. I'll then be armed with info to take back to Water Co / OfWat.

Thanks for your advice all.