No Hot Water & No Idea - pls help, I'm starting to smell

[Orangesofa2]

I have a pressurised hot water system with a Tribune HE single immersion tank, controlled by a Sunvic 207 XL panel.

A few weeks ago I had merely warm water and boosted it by clicking 1hr on the Sunvic. Problem solved and never seen again until yesterday.

Water was again luke warm and the panel was set correctly to come on as always and yet the tank wasn't heating the water. "Not a problem" I thought as I could always throw the immersion switch in the airing cupboard and an hour later I would have hot water whilst I looked into this.

Alas - no. Neither this nor the Sunvic will enable me to heat the water. The Sunvic will 'advance' and '1hr' on the heating side (illuminating the red light) but when I try the same on the hot water side, the LCD display shows it as on but the red light won't illuminate.

I have tried turning the termostat right up on the dual termostat (on the tank) to rule out thermostat 'thinking the water is already too hot' and still nothing.

I am bemused as, to the lay-man (me!), if the Sunvic failed, it would not switch on the HW but the immersion wall switch in the airing cupboard should still work. Plus, if immersion (fed only by the electric from the wall switch which lights up incidentally) does not work, then the Sunvic (which controls the power to the dual thermostat - I think!) should still work...

Surely these two seemingly separate items would not fail at exactly the same time or am I missing something very obvious?

The system was installed 11/2005 if that is relevant. Any help would be much appreciated as quotes to even look at it are starting at just over £200 for which I could buy a new Sunvic, Dual Thermostat and Immersion Thermostat and have more than £100 left to play with....

 

[Agile]

Its unclear to me exactly what kind of system you have.

I would have expected that its a cylinder heated with two imersion elements one near the top and the other at the bottom.

But then you mention heating. What the heat source in your property?

A diagnostic visit should cost about £60-£80 in Bristol. We used to have a very good engineer in Bristol called Chris Hutt but unfortunately he died last March.

If you call cowboys then expect to get cowboys! But at least they told you their charges in advance. You need a heating engineer who is totally competent to deal with electrical faults, not all are. You should look for a no-fix no-fee!

Tony

 

[Orangesofa2]

Thanks for your reply.

I have a gas combi in the kitchen and the pressurised tank in the airing cupboard but must admit am not 100% how the heating works.

The tank is similar to the dual immersion model but it has just one coil set low in the tank.

A neighbour used a local plumber who quoted a low diagnosis charge then proceeded to quote £140 labour to fix plus parts on a relatively simple (apparently) job. It is always that dilema about throwing good money after bad once the diagnosis has been made - pay over the odds to get it fixed or cut your losses and find someone else???

If I could, I would rather look to replace bits myself (assuming I am not risking a life or a flood) as I not only learn but save money too - hence the question to see if anyone has any suggestions.

Failing that - quality tradesmen recommendations would be a great help.

 

[Agile]

The whole point of a fixed price diagnostic fee is that we are paid for diagnosing the fault.

If its simple then the fee includes the fix. If parts or much work is needed then we quote for the repair.

But once the diagnostic fee has been paid you are free to do the repair yourself or get anyone else to do it.

Its still not clear to my why you are talking as if its an electric heater which is not working when the cylinder should be heated by the gas boiler.

Are you sure its a combi? Which hot taps does it supply directly?

Tony

 

[Happyplumber]

Every repair is simple..............................as long as you have the knowledge on how to diagnose the fault,why do you think the man was so expensive because he worked out the fault quickly.

There are now 6 week wonders people who have apparently trained to be heating engineers and plumbers in that short time,they have paid huge amounts of monies to the training companies and are out there with no skill or knowledge and will take wild guesses at what could be the fault


A proper engineer takes a methodical approach and eliminates what it can and cant be and then will diagnose the fault and cost for the repair ,unvented hot water should be treated with respect as this is pressurised and can be as lethal as bomb if you dont know what you are doing ,thats why we have to take an exam just for the privilege of installing and repairing unvented cylinders

No one here should be advising a diyer on repairs to unvented hot water cylinder repairs as this is irresponsible in my opinion

 

[SteNova]

No one here should be advising a diyer on repairs to unvented hot water cylinder repairs as this is irresponsible in my opinion

i agree, but there is nothing wrong with a bit of online text diagnostics, Orangesofa2 before anyone can even guess whats wrong we need to know what you have got, pictures would be a good start

 

[Boilerman2]

You have a Tribune Package (includes Timeswitch pump and control valves,) it sounds like a control or boiler problem you really should get a Registered Gas Engineer to have alook, and one with Unvented G3 certificate would be an advantage because as has been said it is Illegal to work on unvented install of more than 15ltr capacity with out proof of competence (G3) same for the Gas Boiler must be repaired by a competent

 

[SteNova]

thought i would get more info and pics...

"The Range Tribune Pre-Plumbed units are factory assembled and are both pre-plumbed and pre-wired with 230V central heating controls, a pump, two 2-port motorised valves, automatic bypass and a balancing valve. They are also supplied with programmer, room stat and both a central heating & hot water expansion vessel pack."

1. 22mm hot water draw
2. Cold Water Inlet
3. Temperature Relief Valve
4. Cold Feed Drain Elbow
5. Immersion Heater 3kW
6. Twin Thermostat
7. Flow from Boiler
8. Circulating pump
9. 22mm Central Heating 2 port valve
10. Filling Loop Flexible Hose
11. Bottle Air Eliminator
12. 22mm DHW 2 Port valve/safety valve
13. Heating circuit drain elbow
14. 22mm Balancing valve (Lockshield)
15. 22mm Return from radiator circuit
16. 22mm Return to boiler
17. 22mm Automatic by-pass valve
18. Wiring Centre
19. Tundish

 

[SteNova]

also basic test, you say the immersion is wired direct with a manual control and the light comes on, switch it on while someone watches the elec meter, 3kw load should make it go a bit faster

as it's not tripped or blown the supply then it's unlikley to be a short, so it's wiring or the heater is not taking any load

does anyone know if immersion heaters have an expected resistance measurement?

 

[SteNova]

does anyone know if immersion heaters have an expected resistance measurement?

yes they do

across the 2 heating element terminals
should be somewhere vaguely in the region of 20 ohms, but can vary a fair bit.
across the 2 thermostat terminals
should be far below 1 ohm when cold.

 

[oldbuffer]

Sounds as if your hot water can be heated in one of two ways.

1) Via the boiler.
2) Via the immersion heater.

If the boiler option is not working for some reason, then the immersion heater should work (as stated above). If it doesn't, then one possibility is that the high limit (overheat) thermostat has cut out, and this requires a manual reset. If you have the operating instructions, this should say how to do it. If you haven't, give the manufacturers a ring and ask them.

If it is this, and you reset it, but it goes again quite soon, you need to have the cylinder serviced. They are meant to be serviced once a year anyway.

There are other possibilites such as failure of the immersion heater element, failure of the thermostat or power supply problems. Any of these others require the services of someone with the knowledge and equipment to do the checks. Anyone working on non-"user control" parts of an unvented cylinder must have a "G3" certificate.

The above does not fully address (if this is indeed the case) the boiler not heating the hot water, although the high limit thermostat should be wired in series with the zone valve for the cylinder, so that the valve closes if the thermostat goes. If it is this thermostat which needs resetting, it may clear the problems from boiler and immersion heater.

 

[Agile]

should be far below 1 ohm when cold.

If the thermostat contacts had a resistance of one ohm then it would be dissapating 170 Watts.

It would burn out very quickly!

Whilst you dont seem to have much experience of electrical circuits, the OP is likely to have even less and would not be expected to be able to do do any live measurements safely.

After isolating the supplies he could measure the element resistance which is a nominal 18 ohms.

He has not been able to explain to us yet if he has been heating the cylinder with the immersion or the boiler.

Tony

 

[SteNova]

i got the info from here

http://wiki.diyfaq.org.uk/index.php?title=Immersion_Heaters

 

[Agile]

That is not very well written and could be very misleading.

One of its parts says:-

"However the element continues to operate for a fair time by conducting through the water".

That is nonsence. If the casing is split and the heating wire corrodes and breaks the remaining current flow through the water will be VERY small and have little heating effect on the tankful of water compared with a 3 kW element.

A thermostat resistance over about 0.1 ohm will cause the stat to overheat and fail. To be fair, they did say "far below" one ohm.

But we still need to know if the OP is trying to heat water with the gas boiler or electric immersion.

Tony

 

[Bahco]

We used to have a very good engineer in Bristol called Chris Hutt but unfortunately he died last March.

Hi Tony.

Is that Chris that used to post on here