Fitting unvented hot water cylinder
Discussion
Having just installed an Evohome system to my boiler and radiators, it's time to sort out the hot water.
I currently have a basic oil-fired Worcester system boiler suppling the radiators. The boiler is in the attached garage of my 4 bed dormer bungalow.
A vented cylinder in the middle of the house, heated by just an immersion heater, supplies hot water. I have a shower room upstairs, bathroom with separate shower downstairs. Both showers are electric, cold feed from the mains.
The hot water flow rate to the bathroom and upstairs shower is very low (header tank in the loft is barely above the upstairs taps), so an unvented cylinder seems to be the answer.
It will probably be easier to connect the new cylinder if I get it fitted right next to the boiler, in the garage. I feel that it'll be easier to re-plumb the taps than put in the pipework for the primary circuit, and space in the airing cupboard is pretty tight.
The place that supplied the Evohome kit said I can add hot water to the setup easily, just fit a 2-port valve and the associated Evohome electronics. There are no zone valves at the moment, the Evohome kit is taking care of all that.
Access to the tap pipework in the loft looks to be OK.
I also need an automatic bypass valve fitting to the heating circuit, as I don't currently have one (1 radiator left open).
Does this sound like the way to proceed?
Any better ideas?
Rough idea of cost for parts and labour (Cornwall)?
I currently have a basic oil-fired Worcester system boiler suppling the radiators. The boiler is in the attached garage of my 4 bed dormer bungalow.
A vented cylinder in the middle of the house, heated by just an immersion heater, supplies hot water. I have a shower room upstairs, bathroom with separate shower downstairs. Both showers are electric, cold feed from the mains.
The hot water flow rate to the bathroom and upstairs shower is very low (header tank in the loft is barely above the upstairs taps), so an unvented cylinder seems to be the answer.
It will probably be easier to connect the new cylinder if I get it fitted right next to the boiler, in the garage. I feel that it'll be easier to re-plumb the taps than put in the pipework for the primary circuit, and space in the airing cupboard is pretty tight.
The place that supplied the Evohome kit said I can add hot water to the setup easily, just fit a 2-port valve and the associated Evohome electronics. There are no zone valves at the moment, the Evohome kit is taking care of all that.
Access to the tap pipework in the loft looks to be OK.
I also need an automatic bypass valve fitting to the heating circuit, as I don't currently have one (1 radiator left open).
Does this sound like the way to proceed?
Any better ideas?
Rough idea of cost for parts and labour (Cornwall)?
The bathroom and upstairs shower room would both be closer to a tank in the garage, less than half the distance for the bathroom. The kitchen tap would need an extra 5 metres of pipework, so about 30% longer.
The shower room tap is flowing 2 litres per minute, taking 75 seconds to show any sign of warmth, nearly 2 minutes to reach full temperature. The bathroom tap is a little faster flowing, but takes as long to warm up.
My original idea was to just fit a pump, but the builder who did some work on the kitchen suggested an unvented cylinder.
I'll be getting the work done by a suitably qualified plumber. I'm happy to fit radiators and other bits and bobs myself, but I'm not going to mess with a cylinder or boiler, even if the job didn't need signing off
The shower room tap is flowing 2 litres per minute, taking 75 seconds to show any sign of warmth, nearly 2 minutes to reach full temperature. The bathroom tap is a little faster flowing, but takes as long to warm up.
My original idea was to just fit a pump, but the builder who did some work on the kitchen suggested an unvented cylinder.
I'll be getting the work done by a suitably qualified plumber. I'm happy to fit radiators and other bits and bobs myself, but I'm not going to mess with a cylinder or boiler, even if the job didn't need signing off
I use home automation to only spin the recirculation pump when movement is detected in a location that uses water (bedrooms/kitchen)
Most important thing to check is your flow and pressure from your mains. Ideally you need a 22mm feed.
Mine sits at about 55 psi static pressure and flows in the region of 22lpm. I can have a couple of showers running and they are very powerful. A single shower flows about 15LPM flat out.
The cylinder is fed via a 3 bar pressure reducing valve, so anything over 45psi is sufficient. And i would say anything over 15LPM will be ok.
Most important thing to check is your flow and pressure from your mains. Ideally you need a 22mm feed.
Mine sits at about 55 psi static pressure and flows in the region of 22lpm. I can have a couple of showers running and they are very powerful. A single shower flows about 15LPM flat out.
The cylinder is fed via a 3 bar pressure reducing valve, so anything over 45psi is sufficient. And i would say anything over 15LPM will be ok.
I've had a quote to supply and fit an unvented cylinder, 2 port valve and bypass in the garage, just over £1200. The cylinder in the quote is a Centrestore 250, which is around £750 on line.
Is Centrestore a good make?
Do I need such a large cylinder?
It's a 4 bed dormer bungalow, main bathroom and a shower room. Both showers are electric. I don't want to underspec the cylinder for the size of the house, but a smaller one is cheaper to buy and presumably cheaper to heat.
Is Centrestore a good make?
Do I need such a large cylinder?
It's a 4 bed dormer bungalow, main bathroom and a shower room. Both showers are electric. I don't want to underspec the cylinder for the size of the house, but a smaller one is cheaper to buy and presumably cheaper to heat.
Wacky Racer said:
And its because of idiots like him who bodge old copper cylinders that we have modern unvented systems with expansion vessels and pressure relief valves.Youtube has some interesting films of when it goes wrong
21TonyK said:
Wacky Racer said:
And its because of idiots like him who bodge old copper cylinders that we have modern unvented systems with expansion vessels and pressure relief valves.Youtube has some interesting films of when it goes wrong
Wacky Racer said:
"He was fined a total of £500 with costs of £933 and also ordered to pay a £50 victim surcharge."With penalties that severe, amazed it doesn't deter them.
clockworks said:
The hot water flow rate to the bathroom and upstairs shower is very low (header tank in the loft is barely above the upstairs taps), so an unvented cylinder seems to be the answer.
It will probably be easier to connect the new cylinder if I get it fitted right next to the boiler, in the garage. I feel that it'll be easier to re-plumb the taps than put in the pipework for the primary circuit, and space in the airing cupboard is pretty tight.
The place that supplied the Evohome kit said I can add hot water to the setup easily, just fit a 2-port valve and the associated Evohome electronics. There are no zone valves at the moment, the Evohome kit is taking care of all that.
Access to the tap pipework in the loft looks to be OK.
I also need an automatic bypass valve fitting to the heating circuit, as I don't currently have one (1 radiator left open).
Does this sound like the way to proceed?
Any better ideas?
Rough idea of cost for parts and labour (Cornwall)?
I had the same - header tank in loft at a low level, low pressure in bathrooms etc. and decided to go to unvented.It will probably be easier to connect the new cylinder if I get it fitted right next to the boiler, in the garage. I feel that it'll be easier to re-plumb the taps than put in the pipework for the primary circuit, and space in the airing cupboard is pretty tight.
The place that supplied the Evohome kit said I can add hot water to the setup easily, just fit a 2-port valve and the associated Evohome electronics. There are no zone valves at the moment, the Evohome kit is taking care of all that.
Access to the tap pipework in the loft looks to be OK.
I also need an automatic bypass valve fitting to the heating circuit, as I don't currently have one (1 radiator left open).
Does this sound like the way to proceed?
Any better ideas?
Rough idea of cost for parts and labour (Cornwall)?
Found very quickly that a 12 Bar inlet to the house was insufficient to run more than 1 tap because the line in was 15mm. Check your flow - lesson 1.
I then fitted a 200L tank in the loft and twin 3.5 Bar pumps at the outlets, one for each hot and cold feeds.
Now a 12" square shower head will pretty-much scalp you if the taps are opened more than half way. That is a good problem to have.
Although the kids can empty the tank with a 10 minute shower. Shower before the kids - lesson 2.
No idea of costs as I did it myself - a couple hundred for the tank, 150 for the header tank and about 500 for pumps. Luckily I was given a bin full of push-fits in 22 and 15mm so just bought the pipe. Easy enough to do yourself.
The water supply to the stopcock in the garage is plastic pipe (25mm?), which tees off to the loft (taps, header tanks, etc.) in plastic, and the garage, starting in plastic, then reducing to 15mm copper(outside tap, washing machine and boiler filling loop).
The flow rate from the outside tap is just shy of 30l/minute.
Presumably the unvented tank would be connected directly to the plastic pipe, not to the 15mm copper, or doesn't it matter?
The plumber is proposing to connect the hot outlet from the tank to the existing hot pipe in the garage, which is a 15mm pipe that was originally intended to be a washing machine supply. It hadn't occured to me that this would be an option. I thought that it would be a new 22mm pipe up into the loft, connecting to the existing outlet from the old tank (or to the pipes dropping to each tap, if that meant shorter pipe runs).
I feel that putting a length of 15mm between the tank and the bath tap isn't the best way to do it, but I guess that's relative?
The flow rate from the outside tap is just shy of 30l/minute.
Presumably the unvented tank would be connected directly to the plastic pipe, not to the 15mm copper, or doesn't it matter?
The plumber is proposing to connect the hot outlet from the tank to the existing hot pipe in the garage, which is a 15mm pipe that was originally intended to be a washing machine supply. It hadn't occured to me that this would be an option. I thought that it would be a new 22mm pipe up into the loft, connecting to the existing outlet from the old tank (or to the pipes dropping to each tap, if that meant shorter pipe runs).
I feel that putting a length of 15mm between the tank and the bath tap isn't the best way to do it, but I guess that's relative?
oilydan said:
You need at least 22mm going to any more than 1 outlet, where it branches off to the tap you can have 15mm.
Most of mine was already done in 15mm and I could only run 1 tap at a time, until I installed the pumps.
Enlighten me about these pumps? We have lousy hot pressure on the first floor (conventional old school heating and water).Most of mine was already done in 15mm and I could only run 1 tap at a time, until I installed the pumps.
Are these pumps basically like a shower pump but for the whole hot water system, activated by the flow?
Just put one on the hot tank outlet and improved pressure all over?
Seems very simple...?
clockworks said:
I had to google what that was. It would certainly speed things up, not sure about the heat losses in the pipework though. Probably a good idea in a new build, where the circuit losses could be put to good use by heating the rooms. In my house it would just be heating the loft space.
You have to insulate the pipeworkGassing Station | Homes, Gardens and DIY | Top of Page | What's New | My Stuff