Water from hot tap takes 30 secs to get hot using water tank

[endecotp]

I believe it's a valiant ecotec 612

Others have confirmed that that is not a combi, so my guess that you were experiencing the standard problem of combis being slow to produce hot water was wrong.

How far does the water have to go from from the new cylinder to the taps?

You should perhaps ask the installers to explain what is happening.

 

[Agile]

You could work out the volume of the pipe between the UV cylinder that has to be cleared before you will feel the hot water. A little longer as the hot water has to heat up the pipe as well.

But in most properties that's not much more than about 12 seconds but depending on the length and volume of pipe involved.

If it is 22 mm then you could usually change it for 15 mm to get a faster response and waste less water.

Tony

 

[degsy41]

Thanks for all the feedback guys and sorry for not being more descriptive in my posts.
I have a 612 to feed the rads for CH and to keep the water tank at the right temp. I was sold this type by my plumber/heating eng as he said it's a better system that uses less gas and a system which could also accept a solar install I was thinking of getting.
The boiler is in the attic on the gable end and the uv cylinder is right next to it. It has the usual expansion tank fitted to the wall (bit bigger than a foot ball). Next to the cylinder is the pressure accumulator which is about half the size of the uv cylinder, a blue one that looks like an alien alien space ship from a 1950s sci-fi programme.
I believe the pipe work has quite a wide diameter. The plumber who installed it said he chose that but I can't remember the reason he gave. He suggested a circulating pump to solve he delay but I would prefer not to have that due to power it uses and noise.
I could possibly reduce the pipe length to the taps down to about 10m. If I had thinner pipes fitted would this reduce the time taken for the water to get hot?
I thought having the water in a cylinder that was already hot that it would be near instantaneous out of the taps. The delay is getting quite annoying. When I had the water boiler in the kitchen it was instantaneous and it had to heat the water first.
I don't think I'd make a good plumber...

 

[Agile]

Just insulating the hot water pipes can be very beneficial in these cases.

But a 15 mm feed would certainly cut the delay a lot.

Tony

 

[muggles]

A circulating pump for your hot water would be virtually silent and draw about 20w of power, but only intermittently as it'll shut off once the pipes to your taps are warm. It's neither noisy nor expensive to run

 

[endecotp]

Hot water recirculating pumps are very unusual in homes, except perhaps very large ones, because there is nearly always a better and simpler solution to the problem. Are you happy with the pressure of thehot water? If you are, then reducing the pipe diameter to 15mm (assuming it is currently 22mm) would be a good idea. Also, make sure the pipes are insulated and that they don't take unnecessarily long routes.

If you do get a recirculating punp, make sure it has a timeswitch and a thermostat.

 

[dilalio]

OP: get someone to open a hot tap, whilst you are next to the Unvented Cylinder, with your hand on the hot feed pipe coming out of the cylinder. Get them to shout out when they open the tap (or use mobile phones if out of earshot). If you can feel pipe get warm/hot, as soon as you know the tap has been opened, then this will confirm that it is the pipework between you and the outlet that has to be dealt with to shorten the time taken to get the hot water to the tap(s).
If, however, it takes "some time" for you to feel heat at the hot feed pipe, when the tap is opened, then there may be some issue with the top of the cylinder having a pocket of unheated water in it.
Just try this, to confirm that the piperun is the issue.

 

[degsy41]

Thanks so much for all the great advice guys. This helps a lot.
I'll try all the suggestions here.
I'll try to work out the length of the hot water pipes to the sinks and using their diameter to work out the volume.

One question, the pressure accumulator only seems to be feeding the hot water. The pressure of the hot water is far more than the cold, the hot water pressure is very high. If the accumulator is feeding cold water into the hot water supply then wouldnt this affect how long it would take to get hot? I'm thinking that the accumulator should only be feeding the cold water supply and not feeding the hot.
I'm using my logic to try work out an answer here so might have this totally wrong.

 

[Agile]

No, the accumulator feeds the cold water into the base of the cylinder, just like the normal cold feed.

So the hot upper part of the cylinder is unaffected apart from having more pressure to supply it.

Tony