New Thermostat Keeps Tripping.

[j-lo]

Sorry if this is on the wrong forum...bit confusing for first timer.

lived in this rented house 6 years. Ample hot water. Woke up 20th December with no hot water. Phoned electrician who changed thermostat (stat no

1) Had hot water that night but none next morning. He came back and fitted another (stat no. 2) had hot water that night but none next morning. Phoned electrician back but he said I need a plumber.

plumber came out and changed element. No hot water that night or next day.

Phoned electrician who said he was too busy to come back.

next electrician came out said dodgy stat..changed it (stat no.3) had hot water for few days. Then tripped 7 times in 12 hours. Electrician blamed coal fire over heating water. Contnued to trip even though coal fire was not on for days. Electrician changed stat (no. 4) hot water for 2 days then none....and it had not tripped. Electrician said I am just unlucky ( ! ) and changed stat (no.5) .....got hot water that night and then it tripped. I reset and put boost on. Kids had shallow baths

..so tank was not full and hot when I went to bed last night....woke up this morning to cold water and tripped stat.

Getting frustated and landlord is getting a lot of bills!

also sometimes my water was cold in the morning but the stats hadn't tripped at all.

 

[Steve3948]

Is this a top entry Immersion Heater by any chance.

 

[SLIPSHOD & SLAPDASH]

A fairly common problem nowadays since the dual stats are used . If you do a search on this site it has been discussed many times and one particular make  of stat is recommended , if i could remember i would tell now.

Try turning down the temp to about 50, they are not that accurate.

 

[ProDave]

+1 to that question, is it a top mounted immersion heater?

These are notorious for giving trouble.  I think the problem is the secondary safety thermostat must sense the temperature nearer the end, which translates to higher up the tank, i.e. hotter when top mounted.

IF you have a metal header tank, it might be possible to change it for the older type thermostats without the secondary safety trip. that will have been what was there originally.

In the mean time, learn how to reset the over temp trip (TURN POWER OFF FIRST BEFORE REMOVING THE COVER)

 

[Technician]

 Electrician blamed coal fire over heating water.

I have no wish to be a scaremonger but if a fire is used to heat

this water system there is no control over the primary source of

energy.

The water regulations recommend a copper or metallic water tank

as a header vessel in these circumstances.

 

[j-lo]

Thanks. The stat is on top of tank. I always remember to switch off the power when I reset. Yesterday I reset and half hour later tripped again. Water was lukewarm but actual stat was roasting. It wouldn't allow me to reset until it cooled down. Why is the stat tripping and hot when water lukewarm? I appreciate your replies thank you.

 

[ProDave]

Was the water being heated by the immersion or the fire when it tripped, but with only like warm water?

 

[j-lo]

Trips several times every day regardless of coal fire being on. Had no fire on for 4 days there but still tripped constantly. Can reset at 10pm 12pm and again at 2am. Used to hear it heat up overnight but not anymore. Storage heaters still work so npower say nothing wrong on outside meter side.

 

[ProDave]

As it's a rented house I would push the problem back to the landlord.

The only real solution is to change the tank for one with the heater(s) entering from the side.

 

[steptoe]

is it the correct length of stat?

Ive quite often seen short stats [ 7" ? ] used on top entry tanks, when they should be long [ 11or18" ? ]

and if the spark is simply replacing like for like without checking that could cause a problem,,,,

 

[ProDave]

On some of them steps, the overheat stat is surface mounted on the brass flange, so that would be the worst possible type to use for a top mounted immersion

 

[batty]

I did reset a stat in the bottom of a tank at the weekend so even they trip. 

 

[Sharpend]

Can't see how it would happen but if stat is really hot and water luke warm, could it be that there is an air lock within the tank and water level is not high enough, another thought would be the flange ( the name escapes me at the moment) that is inserted into top of rank has a tube that goes into the tank to draw the water from a lower level, if I remember they are designed to prevent air locks although don't believe they are compulsory to fit. Could be that it is the wrong type and not drawing the water that is heated?

Just questioning????

 

[batty]

Surrey.

 

[j-lo]

Thanks for ideas. When water is cold and I have to reset the stat and put the boost on (2 hour) sometimes I get a small amount of hot water (1shallow bath) or more usually no hot water at all. Even on twice (so 4 hours for nothing) could it be a fault in the actual control box that has the boost on. Its a hortsman e7 . Electrician is going to try replacing the thermostat (no. 6) and element again...but I'm not optimisitic. Problem ongoing since 20th december.

 

[says-les]

If stat trips with no hot water, what is heating the stat, I ask myself? Direct heat from element?

It is the landlord's responsibility, and you should let him know, and he should deal with it.

Keep us baffled sparks informed please.

Cheers

 

[ProDave]

If you have already had 6 visits, then surely the landlord must be realising it might just be cheaper to swap the tank for one with a side inlet heater, and all your (his) problems will be gone.

 

[Nelson]

Hi I would guess that the thermostat pocket is touching on the element Possibly the 1st stat was faulty but as the stat was replaced the angle of the stat pocket was changed so it is now in contact with the element ? I would take out the stat insert a screwdriver into the pocket and use the lever to angle away from the element just a touch. It's very common for thermostat pockets to contact on elements when being installed