Hi,
A couple of weeks ago I had an ageing open vented boiler replaced with a Baxi duotec 40 in preparation for a loft conversion - the installer had measured my flow rate at the outside tap at 16 litres/min, and I wanted as much flow as possible to cater for the possibility of two showers running - hence he felt the big boiler would suit, and I had the flow rate to support it (but not enough for a megaflo). The boiler is sited on the first floor in the airing cupboard.
I had separately checked the bath tap in the main bathroom on the first floor, and measured it delivering 16 l/min from the tanks in the loft, before the new installation.
After the install, I'm finding the first floor shower over the bath is definitely an improvement over the old system, but the bath flow is down to 8-12 litres a min and so much slower to fill than before. Also, when the bath taps are running I get literally a dribble out of either hot or cold tap on the first floor (though downstairs is ok).
I got the installer back in, and he checked the pressure - it was 2.1 bar at the outside tap, but using the pressure gauge on the boiler it would only fill the central heating circuit to 1.6 bar. This drop he explained was indicative that I would see a reduced flow rate, though was surprised it was so great. With only that flow of water, it would seem that two showers running would really be pushing it, and I'm concerned the 2nd floor bathroom will suffer even more.
So, my questions are:
1 - why would my pressure have dropped so much on the first floor - would I only expect ~0.3 bar drop between ground and first floor ? The pre-existing pipe routing is a bit bizarre - it goes from the ground floor via the loft and back down to the boiler in 15mm pipe - would this explain the problem?
2- would the excessive pressure drop explain the reduced flow rate to boiler and bath ?
3 - is there anything worthwhile I can do to improve it to get the full 16 l/min I have coming into the house?
4 - will I have even more problems when loft conversion on 2nd floor (in progress) - I assume the shower pressure will be down to 1.3 bar in the loft - will that be sufficient, and will the bath up there be even slower to fill?
5 - if the 40kw boiler can't get/deliver 16 l/min, have I ended up with an over-specced system that is more expensive system to buy/run? Is it reasonable that the installer wouldn't have foreseen this by doing appropriate checks (he never actually measured the pressure for example), and do I have grounds to ask him to sort this out, or is it one of those things?
Would appreciate any input and advice.
A couple of weeks ago I had an ageing open vented boiler replaced with a Baxi duotec 40 in preparation for a loft conversion - the installer had measured my flow rate at the outside tap at 16 litres/min, and I wanted as much flow as possible to cater for the possibility of two showers running - hence he felt the big boiler would suit, and I had the flow rate to support it (but not enough for a megaflo). The boiler is sited on the first floor in the airing cupboard.
I had separately checked the bath tap in the main bathroom on the first floor, and measured it delivering 16 l/min from the tanks in the loft, before the new installation.
After the install, I'm finding the first floor shower over the bath is definitely an improvement over the old system, but the bath flow is down to 8-12 litres a min and so much slower to fill than before. Also, when the bath taps are running I get literally a dribble out of either hot or cold tap on the first floor (though downstairs is ok).
I got the installer back in, and he checked the pressure - it was 2.1 bar at the outside tap, but using the pressure gauge on the boiler it would only fill the central heating circuit to 1.6 bar. This drop he explained was indicative that I would see a reduced flow rate, though was surprised it was so great. With only that flow of water, it would seem that two showers running would really be pushing it, and I'm concerned the 2nd floor bathroom will suffer even more.
So, my questions are:
1 - why would my pressure have dropped so much on the first floor - would I only expect ~0.3 bar drop between ground and first floor ? The pre-existing pipe routing is a bit bizarre - it goes from the ground floor via the loft and back down to the boiler in 15mm pipe - would this explain the problem?
2- would the excessive pressure drop explain the reduced flow rate to boiler and bath ?
3 - is there anything worthwhile I can do to improve it to get the full 16 l/min I have coming into the house?
4 - will I have even more problems when loft conversion on 2nd floor (in progress) - I assume the shower pressure will be down to 1.3 bar in the loft - will that be sufficient, and will the bath up there be even slower to fill?
5 - if the 40kw boiler can't get/deliver 16 l/min, have I ended up with an over-specced system that is more expensive system to buy/run? Is it reasonable that the installer wouldn't have foreseen this by doing appropriate checks (he never actually measured the pressure for example), and do I have grounds to ask him to sort this out, or is it one of those things?
Would appreciate any input and advice.
