Ask The Trades - CH and hot water problems

mercedesjb

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CH and hot water problems
Oct 8^th, 2006, 8:58am

I have a gravity fed/pumped ch system

I had endless problems last winter, but the current problems are as follows;-

during the summer months when the ch was switched off we could easily fill the bath with hot water.
now that the ch is switched on the hot water is not as hot, and only fills about a third of the bath before going cold!
also when the ch was first switched on only 2 radiators upstairs were hot. bled all the rest, but NO AIR. They eventually came on but not hot enough, same as last winter!
bled the vertical air pipe next to the tank and all the rad's seem to have improved.

things that have been done:-
had a new tank thermostat, divertor valve, a flushing solution put in ch system for the required time,drained and an inhibitor put in(as there was a lot of sludge in system)
the stat on the boiler is high enough, the stat on the tank is at 60degrees.
a new ball cock assembly fitted to the expansion tank.

the pipes from the boiler are very hot(as they should be)

the only thing we are not sure about is whether the pump that was changed about 4 years ago is faulty - it is very hot to touch, but it would be.

the question is - could a faulty pump cause all these problems? or is it something like the programmer?

just a quick added note- when the ch and hot water switched on the programmer this morning - a I pressed the 'extra hour' button there wasnt the usual 'firing up' noise, just the sound of the water gurgling
is this normal just after the system has stopped?

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« Last Edit: Oct 8^th, 2006, 9:11am by mercedesjb »

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CWatters

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Re: CH and hot water problems
Reply #1 - Oct 8^th, 2006, 9:26am

Is it possible that the priority is the "wrong" way around eg...it's configured so that heating has priority over HW. The problem with the rads might be causing the heating to be on 90% of the time leaving little or no time for the HW.

With everything cold and both room thermostat and HW calling for heat see if the valve sends water to the cold tank or the rads first.

It sounds like you've still got sludge or an air lock in the pipes. We had a similar problem with the rented house we are in. Only the upstairs rads got hot. Solved by turning off all the rads except one. Got that hot then turned on the others one at a time leaving plenty of time betwen each. Forcing the water through seems to have stirred up the sludge that settled when the house was empty for a short period.

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thescruff

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Re: CH and hot water problems
Reply #2 - Oct 8^th, 2006, 9:50pm

Trying to get the head round your post Roll Eyes

You say you have gravity primaries to the cylinder yet you have a divertor valve, is it a divertor or flow share valve, and what does it divert. The hot water issue could be the cylinder is scaled up or full of scale depending on age.

Again if you have gravity primaries the pump is for heating only, any gurgling is air in the system.

What boiler make and model is it, and can you post a few pics of the working bits, e.g. pump cylinder, valve etc.

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mercedesjb

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Re: CH and hot water problems
Reply #3 - Oct 8^th, 2006, 11:23pm

the model of the boiler is ideal mexico 2

just out of interest i switched the CH off leaving just the hot water on about 40 mins before taking a bath and there was adequate hot water!

took some pic's - can't work out how to upload them

however the so called divertor valve has a lever pretruding and has 'man' written on right side of lever

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« Last Edit: Oct 8^th, 2006, 11:32pm by mercedesjb »

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thescruff Global Moderator Trade Member Author Offline Who said plumbing was easy. Posts: 6037 Total Thanks: 147 For This Post: 0 Gender: Trade: Plumber	Re: CH and hot water problems Reply #4 - Oct 9^th, 2006, 7:30am Unfortunately I have to go to work so wont be able to see them till later. Save the photo's in Photo bucket or similar, and then just copy and past the {IMG} tags, alternatively email them to me. I still cannot figure out why the divertor valve, what controls it ????
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mercedesjb GDPR opt-out Total Thanks: 147 For This Post: 0	Re: CH and hot water problems Reply #5 - Oct 9^th, 2006, 9:26pm hi, please find images as requested - i hope it works!
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thescruff

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Re: CH and hot water problems
Reply #6 - Oct 9^th, 2006, 10:33pm

Ok so we don't have gravity primaries it's a fully pumped system.

Back to the valve then, is it a divertor or flowshare, Number on top, how many wires, looks like an Honeywell.

When you bleed the rads/system did you manually open the valve, on the end with the cable is a lever which hooks around the lug for filling, to the right in your picture.

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mercedesjb

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Re: CH and hot water problems
Reply #7 - Oct 9^th, 2006, 10:55pm

it is a honywell - no numbers on it - it said divertor on invoice!
it has 'man' and 'auto' on either end of slide lever. not sure how many wires inside covering

I dont understand what you mean about the bleeding? - lever for filling?

I bled the radiators with the system off using the bleed screws and the the riser pipe as well

2nd night turning ch off 45mins before bath and plenty of hot water!!

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Re: CH and hot water problems
Reply #8 - Oct 9^th, 2006, 11:05pm

If you look at your second picture, you will see a lever which you can push to the right and hook it over the nitch in the metal, you have to do this or the valve is closed and you cannot bleed (the air out) of the radiators properly.

THe number will be on the silver body of the valve, if as you say its a divertor valve then you can only have hot water or heating and not both, it should be a flowshare valve.

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« Last Edit: Oct 9^th, 2006, 11:05pm by thescruff »

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Re: CH and hot water problems
Reply #9 - Oct 10^th, 2006, 7:45pm

Hi Scruf,

Could you explain the difference between a diverter and a flow share for me.

In the system I'm most familiar with the valve sends all the hot water from the boiler to either the rads or the Hot water tank. It's usually controlled by the thermostat on the H/W tank. If you turn on both then the boiler heats the H/W tank first and only when that is upto temperature are the rads heated. So you eventually have both H/W and heating.

Is that a diverter type system? What does a flow share valve do?

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« Last Edit: Oct 10^th, 2006, 7:47pm by CWatters »

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thescruff Global Moderator Trade Member Author Offline Who said plumbing was easy. Posts: 6037 Total Thanks: 147 For This Post: 0 Gender: Trade: Plumber	Re: CH and hot water problems Reply #10 - Oct 10^th, 2006, 10:49pm 2 Fs please You are correct CW, the divertor valve will send heat to either port depending on call or priority. The more common flowshare/mid position valve will send heat to either port or both. Divertor valves are very seldom used for hot water/heating control simply because you cannot program both at the same time
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mercedesjb GDPR opt-out Total Thanks: 147 For This Post: 0	Re: CH and hot water problems Reply #11 - Oct 10^th, 2006, 11:44pm so, I wonder, is it possible that when the plumber changed the valve it was a diverter not a flow share and thats wht we have had the lack of hot water problem since then. is it the same fitting?
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Re: CH and hot water problems
Reply #12 - Oct 10^th, 2006, 11:59pm

Quote:

so, I wonder, is it possible that when the plumber changed the valve it was a diverter not a flow share and thats wht we have had the lack of hot water problem since then. is it the same fitting?

It looks the same, but the insides and head are different, the valve body is the same size.

It could also be wired up in reverse, giving heating priority instead of hot water.

yes this is why I keep asking about the valve, in my opinion its the wrong one, there will be a number on the silver head.

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« Last Edit: Oct 11^th, 2006, 12:01am by thescruff »

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mercedesjb GDPR opt-out Total Thanks: 147 For This Post: 0	Re: CH and hot water problems Reply #13 - Oct 11^th, 2006, 12:51am definately no number on it. I think I might get another plumber to come and physically check it out to see what's been fitted and how thanx for all you advice and time 'thescruff' I will let you know out of interest what the outcome is
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CWatters Super Member Offline "Daddy fick it" says James Posts: 5150 Total Thanks: 58 For This Post: 0 Gender:	Re: CH and hot water problems Reply #14 - Oct 11^th, 2006, 10:47pm thescruff wrote on Oct 10^th, 2006, 10:49pm: 2 Fs please Oops sorry. I should know better as I get called Walters all the time. Thanks for the info on valves.
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thescruff Global Moderator Trade Member Author Offline Who said plumbing was easy. Posts: 6037 Total Thanks: 147 For This Post: 0 Gender: Trade: Plumber	Re: CH and hot water problems Reply #15 - Oct 11^th, 2006, 11:42pm Quote: definately no number on it. I think I might get another plumber to come and physically check it out to see what's been fitted and how thanx for all you advice and time 'thescruff' I will let you know out of interest what the outcome is If you get another plumber, make sure he is ok with system electrics
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mercedesjb

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Re: CH and hot water problems
Reply #16 - Oct 25^th, 2006, 7:08pm

Thescruff
well, the plumber came and did the following;-
changed the pump(temporarily) - no differance
removed all the radiators and flushed through with hose pipe-no differance
removed the cylinder and did the same-no differance
cut into the return pipe to the boiler and flushed that through, and finally we got some hot water back

all seemed fine for a few day's, except ,the radiator in the upstairs bathroom has never got hot(even supply pipe is cold), and the main bedroom is only luke warm.
but now again there is a lack of volume of hot water
what the h..l am I to do - this problem seems endless!!!

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thescruff Global Moderator Trade Member Author Offline Who said plumbing was easy. Posts: 6037 Total Thanks: 147 For This Post: 0 Gender: Trade: Plumber	Re: CH and hot water problems Reply #17 - Oct 25^th, 2006, 9:56pm Take another pic of the pump and the connections behind the cylinder and email them to me, not so close this time, I need to see all the pipes and fittings. scruff2@blueyonder.co.uk
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