Hot water is running out too quickly

Viscount

Hi all,

We seem to running out of water a bit too quickly and i've noticed over time (last 5 years) that the amount of hot water we get from the cylinder is getting less and less. We get around 1 1/2 showers worth now before having to use the immersion heater.

Crystal ball background info..

Our boiler is a 1970ish ideal Standard Type 2 CF floor standing in the centre of the house. It has a simple boiler control which controls how much gas it is using. That controls the hot water for cylinder and radiators, there is no thermastat, but all radiators have TRV's including one directly leading to the actual hot water cylinder which is set to max.

Just before we use the shower I've checked the cylinder is hot down to the bottom which it is.
We've had this heating system since we moved into the house 2006 and prior i've only lived in houses with modern combi boilers so have had no experience of older systems to go on.

so i'm wondering whether 1 1/2 worth of showers is actually consistent with hot water cylinders and if not where is it all going?

On the plus side the boiler has been fault free...

keystone

1. Sorry don't beleive you have a TRV on the cylinder. I think you meean something else.

2. When you say there is no thermostat I presume you mean no roomstat? Is there a stat on the cylinder? There has to be a boiler stat.

3. Unless you can quantify what consitutes 1½ showers there is very little that can be done to help you. If you/someone stands under it for 90 seconds + 45 secs then something is wrong. If you/someone stands under it for 30 minutes + 15 mins that's a different matter. In the latter case you are emptying the cylinder and thats a usage issue not a technical one.

As a matter of interest why is this suddenly a concern after 6 years? Has it always been a concern and you haven't [STRIKE]bothered[/STRIKE] been concerned enough to ask previously or has something changed?

Cheers

Viscount

Hi keystone

The TRV or what looks just like a TRV to me is on a pipe that is leading into the hot water cylinder at the bottom.

Yes I think i mean room stat, sorry got the technical bits mixed up. There is a control on the boiler which controls how much gas is going into the boiler I guess that's the thermostat. Its purely mechanical.

one shower would mean 5-10 mins max.

its been getting worse over the course of time so i'm wondering whether to keep putting up with it or get an idea of what could be wrong. Prior to this we were not [STRIKE]concerned[/STRIKE] bothered too much but just recently talking to someone else with a similar system they said that didn't sound right to them and they got a lot more hot water out of theirs.
Additionally as we are using the immersion heater more and more I'm starting to ask how much is this costing us so that plus this equals why are we not getting much hot water out the cylinder?

keystone

Viscount wrote: »

The TRV or what looks just like a TRV to me is on a pipe that is leading into the hot water cylinder at the bottom.

Any chance of a pic. You won't be able to link directly being a new user but if you get the url from the hosting site. Insert in a post as text but remove the http bit then one of us can put it back in.

Yes I think i mean room stat, sorry got the technical bits mixed up. There is a control on the boiler which controls how much gas is going into the boiler I guess that's the thermostat.

OK no worries.

one shower would mean 5-10 mins max.

Mmm. So thats between 7 and fifteen minutes at (say ) 9 litres a minute = somewhere between 60 and and 160 litres. So it could be right on the edge at the larger end of the window especially as you say:

Just before we use the shower I've checked the cylinder is hot down to the bottom which it is.

so I suppose another question is what is the size (from a volume perspective) of your cylinder?

its been getting worse over the course of time so i'm wondering whether to keep putting up with it or get an idea of what could be wrong.

Might be a scale build-up.

Cheers

penrhyn

There used to be a thermostatic valve for HW cylinders. Cyltrol if I recall correctly.

http://www.hav.co.uk/products/shw-detail.asp?pid=12803&cid=1002
Probably gone faulty.

27col

A Cyltrol valve, now that's a blast from the past. I had one of them and an Ideal Standard boiler when I built my first house in 1966. I think that the boiler is long overdue for replacement. Very inefficient by today's standards.

penrhyn

Yes it was about that time I first came across them.

Viscount

Pic of what looks like a TRV to me. add http://

i876.photobucket.com/albums/ab329/Iskador/100_0710_zps3f06f8a6.jpg

The size of the cylinder is hard to measure since its got its lagging all over it, however roughly its about 1m x 0.5m. Doing a bit google search leads me to believe it could be a 18x36inch sized?

27col: we had considered replacing it when we moved into the house but thinking about it more closely the efficiency savings we were told we could save up to £200 off our heating bill per year.
Taking into account the cost of replacing it c. £5k, would take us 25 years to make up the cost.
Given that I've heard from many people new boilers are pain in the you know what, in both servicing and longivity, we thought it best to keep the old 1970's boiler as over time it was better value for money.

So far servicing it is very cheap as there is hardly anything to do to it.

Downside is its a bit quirky like we can have hot water and heating but not hot water only unless you switch off the TRV's. Otherwise you switch the boiler off and just use the immersion heater.

keystone

Viscount wrote: »

Pic of what looks like a TRV to me

Looks exactly like a TRV to me but goodness knows what is doing there:


Any chance of some more pics of the overall layout of piping around the cylinder? Sorry to be a pain.

The size of the cylinder is hard to measure since its got its lagging all over it, however roughly its about 1m x 0.5m. Doing a bit google search leads me to believe it could be a 18x36inch sized?

It was the volume I was interested in rather tha the physical size TBH. However the physical measuremnets suggest irt could be on the small size but difficult to be definitive without knowledge of the approx diameter.

Downside is its a bit quirky like we can have hot water and heating but not hot water only unless you switch off the TRV's. Otherwise you switch the boiler off and just use the immersion heater.

Further pics as requested above may help with that. If theres one bit of bodgery in there there could well be more.

Cheers

Viscount

according to a google search if it is a 18x36 the volume is 117 litres.

I can get more pics but it will be tonight once i've finished work.

penrhyn

Looks like one of these to me.
http://www.plumbcenter.co.uk/en/drayton-trv4-temperature-relief-valve-4-remote-sensor-capillary-2-m-18048?top_category=18233

Quoted temperature range 0 - 30 degrees c. No wonder the water is not being heated to the required temperature. I'd pull the capilliary sensor off the tank, and see what happens.

On the other hand it could be one of these.http://www.plumbcenter.co.uk/en/heating/domestic-controls-valves/drayton-tap-thermostat-2-way-comes-with-so-sensor-15mm-56859