Help! No hot water..

[Misty9]

We live in a rented house and the boiler is a glow worm space saver mkII (and looks almost as old as the house...) which I don't think is a combi boiler. There's a separate immersion tank in ds's room anyway.

Since yesterday the hot tap water will only come out lukewarm. The heating still works fine and radiators get hot. The only change is since the warmer weather (hurrah!) I have switched off the heating save for an hour 5-6pm. Does this mean the water won't have a chance to heat up at all? I can't remember what one needs to do with a non-combi boiler..

There also seems to be an air lock issue or something as the water comes out in gushes - and almost seemed to stop coming out of the hot water tap on the bath this evening (poor ds was filthy enough to need a lukewarm bath).

What's going on? I thought it might be quicker to post on here than wait for the managing agent to get their arses into gear...

You should be able to turn off the central heating by turning down the room thermostat on the wall.

The boiler programmer should have separate time settings for HW and CH.

You should not need to turn the boiler off.

The boiler should be able to heat the hot water cylinder without using the CH.

Is yours a house or a flat?

How many cold water tanks are in the loft and how full are they?

When you say gushes of water out of the tap do you mean air comes out like the water is running out? Does it improve if you stop running the taps for five minutes?

How is the hot water cylinder insulated and what colour is it?

When was the boiler last serviced and have you been given a copy of the Gas Safety Inspection Certificate? If not demand one.

Hello pigletjohn, I was hoping you'd come along :)

There is no room thermostat, just a control box on the wall by the boiler on which we can only set times for the heating to come on and off (or 'off' or 'constant')

Don't know about tanks in the loft as we're not allowed to go up there (and have no means of doing so), but the tank in ds's room is yellowy orange in colour and has a few wheel tap controller type things (iykwim!) with a sort of radiator valve control set to '6' coming out of it.

Gas safety - yes, and the sticker on the boiler says it was serviced less than a year ago.

Had heating on today and the water is warmer, but not as hot as it has been. Also, the shower water isn't getting hot...not sure what type of shower but separate enclosure to bath and affixed to the wall?

Water was sort of inconsistently gushing out the taps...sorry, can't think how to describe it but yes a bit like its about to run out.

Oh, it's a house :) Victorian terrace jobby.

Help! I need a shower! oh, and if it turns out a plumber is called unnecessarily, we get charged...money grabbing letting agents

Oh, if this is relevant, all the radiators have thermostatically controlled valves on them; however, none of these appear to work and the only way to turn the heat down is to turn the radiators off...

Google "Drayton Tapstat'

Is it one of those?

Examine your programmer more carefully. It should have separate buttons or sliders for HW and CH. What words and numbers are on it?

Where have you been turning the boiler off?

Do the radiator knobs show any sign of leakage round the spindle? If not you can use them to turn off the radiators but there really should be a room stat.

That tapstat thing looks a bit like the one coming out of the hot water cylinder... Ds is asleep as the moment so I can't check.

Sorry, I meant turn off the boiler at the control box, nothing to do with the actual boiler.

As for the box, it really doesn't have anything to specify ch or water on it. There is a digital display for the time and you can adjust times for 'on' or 'off' heating programmes. Then there's a vertical sliding switch for the options of on, off, auto, all day etc. there's a +1 hour switch and an advance switch. Both manually override the set programme. Then there's another vertical sliding switch to choose between run, set prog, set time.
That's it!

No room thermostat that we've come across as yet...been here just over a month.

Apparently the landlady is going to come and look at it (she used to live here) so at least if anyone calls a plumber it'll be her.

Oh, and I just checked and the shower is getting hot now so I can get clean at least! But I'm pretty sure it's not right if we can't have hot water without putting the heating on??

I had to bleed a lot of the radiators when we first moved in too, if that's relevant.. Couldn't figure out a way of topping up the boiler either. No manual.

that boiler doesn't need topping up, it is fed from a small tank in the loft.

if the programmer has a digital display it must be quite modern. Possibly some incompetent oaf has fitted one intended for a combi boiler, where there is no time setting for the HW. However if we knew the make and model it is possible that there is some way of controlling it.

As you have a tapstat, your system has (or had, if it was later changed) pumped flow to the radiators, and gravity flow to the cylinder. Gravity flow is slow so may take a couple of hours to warm up the cylinder. It will be more economical if you insulate all the hot pipes between the boiler and the cylinder with Climaflex or similar, otherwise they will act as long thin radiators all summer.

Your system ought to have a room stat which turns the CH pump on and off according to demand for heat. It sounds rather as if there is no stat so the pump will run all the time the boiler is on, even if the house is warm, which is bad. Even worse, it sounds as if there is no separate control of the HW and CH, so that to heat the cylinder, you turn on the boiler and the CH pump starts, even in midsummer.

Compounding this poor installation, your TRVs, you say, do not seem to work, so whenever you try to heat the cylinder, the radiators heat up. This will waste a lot of energy and heat.

I suspect that the person who fitted the (new seeming) programmer did not know what he was doing, so cannot have been competent.

The simplest and cheapest correction would be to fit a room stat so that it turns the pump on and off. Any competent heating engineer and most plumbers could do that in less than an hour. You can buy a simple room stat for less than £10 though better programmable stats are more expensive.

Thanks pigletjohn. And yes, you've got it in one. Landlady has been in touch by text and says that in order to have hot water but not heating, we have to turn off the radiators!! Absolutely ridiculous. Apparently there is also some sort of switch in the airing cupboard to shut down all the radiators simultaneously. Will have a look later.

I am not impressed. Might suggest the room stat to her, but she evidently thinks there is no problem with how the system functions!

Worst case scenario, in summer do you think having the boiler come on for an hour in the morning and evening will suffice for hot water? Obviously with all the rads turned off... Our bills are going to be enormous aren't they? :( even more reason to buy our own place asap.

Oh, and there is no make or model on the timer box - there are slots suggestive of the ability to take the cover off, how would I do that? Might shed some light...

the switch might be to rurn the pump off. only an idiot would do it that way instead of fitting a thermostat though.

gravity feed to cylinder might take two hours or more. If you are near the boiler you will notice it fires less and less often as the cylinder warms up, and then almost stops. The tapstat (if it is working) shuts off the flow through the cylinder once the cylinder is hot, then the boiler just fires occasionally to keep itself hot and to act as an unwanted radiator.

I can understand that there is no problem for her, since she doesn't pay the gas bills or live in the house.

I think you ought to write to the managing agents later, as a "maintenance problem" saying that the TRVs don't work and pointing out that this is important since there is no room stat. Keep a copy. TRVs are not adequate on their own if there is no thermostat.

Depending on quality of make TRVs usually stop working after ten years or so.

Thanks for all your help. I more meant that as she's lived in the house previously for a number of years, she evidently doesn't see a problem..

Might explain the F rating on the EPC :( knew that should have been a red flag.

see if you can find a programmer that looks anything like yours on here

ACL Drayton and Honeywell are the most popular good quality controls but I would not be surprised if your house has some cheap rubbish.

Don't try to open it.

Oh, and I reported the TRVs not working as soon as we moved in. They didn't seem too concerned and just said that's how they are! Might write a letter though.

Nope, it's not on that website, but thanks for looking. I'll not try to open it then :)
I would take a picture but don't think I can upload on my iPad for some reason.

Picture on my profile :) upside down...

can't see your profile.

Sorry, should be able to now...

could it be a Danfoss? not this model but perhaps a family resemblance

big pic

nope, still can't see you.

can see it now

don't recognise it but it might possibly be a very old Honeywell

they still make [http://www.screwfix.com/p/honeywell-st699-programmer/86588;jsessionId=G9xYRnVQVJmbq4MpDfXFJvDp8hPy8qsZ23rST1GnbKnndl7yc37Z!1949254094!1366201632033 this one,]] and it is an old design they sell at a high price to older people as replacements or if they want something really simple. Is there a resemblance?

Doesn't matter now as I reckon the existing wiring design and installation has been done so badly and is the cause of your problem.

here is a very cheap and basic thermostat. It should be fitted in the living room not the hall, landing or bedroom.

The Honeywell CM907 Room Thermostat is very much better (and more expensive) and has its own multiple settings of temperature according to time of day and day of week.

No, nothing like that Honeywell. If we got the room thermostat fitted that still wouldn't solve the problem of having to put the heating on every time we want hot water would it?

Worst case, what's the least inefficient way of timing the boiler to come on do you think? Two hours either end of the day? For how long would the water cylinder stay hot? Ds has a bath every other day at 5.30ish, and we have showers in the morning once a week but we need hot water for washing up throughout the day.

I've texted the landlady but not holding my breath she has replied but I'm too scared to look as my text was possibly a teeny bit annoyed tone

Hmm, well it's as expected and things will stay as they are. Landlady reckons the bills were fine when she lived here. Is going to ask agent to check TRVs though, so that's something.

We'll just have to turn all rads off when it gets consistently warmer and hope for the best re bills I guess :(

Thanks for all your help pigletjohn. Another thing to add to the checklist when looking at rented properties it seems!

if you can get a thermostat fitted (or the switch works) then at least the pump will not be sending hot water round all the radiators, which will help. Then you can set the timer for such times as will fill the cylinder with hot water. If you feel the "return" pipe coming out of the cylinder below where the tapstat is, it will co cooler once the cylinder is hot and the tapstat closes. Get an idea of how long the boiler takes to get it fully hot. It might be a couple of hours or so. If it was your own house I could describe how to update it and it would heat faster.

Some warm water will drift into the upstairs radiators so turn them off during summer.

The yellow cylinder insulation is quite old, you can improve the insulation a bit by putting a red jacket over the top (but not over the cap of the immersion heater) and putting Climaflex or similar over the hot pipes. They are probably 28mm diameter which is uncommon, so you might have to get a few metres from a plumbers merchant. 22mm and 15mm are available in all DIY sheds. The cylinder will stay hot for more than 24 hours until you use it all. A bath uses about 100 litres which is about what most cylinders hold

If you had an uninsulated cylinder it would waste very much more.

Experimentally read the gas and electric meters every day. You might find it uses about a metre of gas a day for hot water in summer, which costs about (1 cu m = about 11.1 kWh at about 6p =) 66p.
my much more efficient and modern boiler, controls and cylinder use about half a metre per day in summer.

There is probably an immersion heater in the top of the cylinder which will use (3kWh per hour at about 14p = ) about 42p per hour until the cylinder is hot. You will be able to see when it stops because the electricity meter will stop flashing or whizzing round. It is likely to cost considerably more than using the boiler. but try it for a couple of days and watch the meter readings to see.

some insulation products not subsidised this year.