Mains pressure hot water systems, vented or unvented?

Elvis_Fan

We have just bought a 3 bed house that needs a complete upgrade of the heating system including new boiler, rads, tanks etc(only the pipe work is still fit!).
We have been quoted £2480 for a Megaflow and £2000 for a Tribune both of which are pressured unvented systems, does this seem about right?
We expect the vented system such as Thermflow to come out about the same.
Discounted a combi boiler due to the flow rates

Would like to know about other people's experience/knowledge on these systems and if they provide any long term benefit/problems over the traditional header tank set up? Also what other manufacturers are out there.

fluffymuffy

I love mains pressure hot water systems - our last house had one. It meant we could have a tank downstairs and keep the loft completely free of tanks (using a direct feed to the boiler). Also we had a thermostatic mixer shower which delivered the precise temperature on the dial at a higher pressure than with tanks. Our old system (Vailant) came with a big expansion vessel - like an egg which sat on top of the cylinder. The cylinder had a sacrificial anode which cost about £30 to replace every three years - we did have quite aggressive water and I don't know whether the anode was needed because of the higher pressure.

Elvis_Fan

I keep getting conflicting advice on these, a company I just spoke to said that having a pressurised system would increase my house insurance?
There doesn't seem to be a lot of advice out there regarding these. Everyone I have spoken to that has a mains pressure hot water system swears by them and it seems that Megaflow are the main brand.
Has anyone any experience of
Pandora by DPS
Thermflow
or Tribune

or any other makes out there. I looked at Gledhill (Boilermate) but have been told they have gone out of business?

casper_g

I've lived in three rented homes with combination boilers, and never had a problem with flow rates. In one the pressure was a bit too high if anything, and I tended to get wet feet when turning on the kitchen taps. It seems to me that you'll only get pressure issues if the boiler is under-specified in the first place.

brig001

We have an old vented Albion Mainsflow thermal store and have no problems with it. We have mains pressure hot water at a high flow rate while only needing a simple boiler. I would check servicing costs of an unvented cylinder before choosing, as these are supposed (according to some manufacturers) to be serviced annually by someone holding G3 certification.
HTH,
Bri.

TrishaM

I have a megaflow. which runs 3 showers, with thermastatic shower valves. Love it. No water pipes in the loft, and my house insurance isn't affected. In fact they have never asked about this.

Bikertov

I have got a Range Tribune tank, and LOVE it ...

We gutted the house when we moved in, and went for mains pressure. No tanks in the loft (load of space as we did a loft conversion). Great water pressure as we have 3 BAR (it helped we also had a new 32mm main installed), so no shower pumps needed.

We never run out of water, like the old house did - I often used to drain the cold tank and then get air locks. The tank (heat) recovers SO quickly, that I can stay in the shower for 30 minutes asd never run out of hot water.

Also, mains cold water everywhere means drinking water everywhere.

It may cost a bit more than a vented system, but you save on tanks, pumps for showers etc.

Elvis_Fan

Thanks, that's great.
I am pretty sure I am going to go for a Range Tribune with a twin coil to give me the option of adding solar heating at some point. They seem to be the most cost effective and simple to install.

swagman

One comment from a plumber when we were deciding whether pressurised or not, is that if you are proposing to re-use existing pipework formerly part of a vented system, the pressurised system may find leaks in the old pipework joints.
This may not matter if all old pipework is accessible, but if not it may mean extra expense, to the extent of replacing all pipework.

deano72_2

swagman wrote: »

One comment from a plumber when we were deciding whether pressurised or not, is that if you are proposing to re-use existing pipework formerly part of a vented system, the pressurised system may find leaks in the old pipework joints.
This may not matter if all old pipework is accessible, but if not it may mean extra expense, to the extent of replacing all pipework.

yep thats correct,i converted mine to mains pressure,excisting pipework was fine but one of the rads leaked on a weld joint so its just not your pipework

arfurrrr

Ask your installer to look into viessmanns 100/200 boilers with their vitocell stainless steel unvented cylinders , these are fantastic a 4 pipe sytem with internal diverter valve . No 2 port safety valve required , no s plan or y plan and a thermistor not a stat controlling the cylinder temperature . If you local to Leeds , i`m happy to quote and can provide references/telephone numbers of jobs instaled .