Drayton room stat - how to bypass it

[beesley121]

Hi guys,

me being not that good with electrics, I want to eliminate a room stat from a problem I have where I have hw but no heheating the stat has 3 wires. A live, a neutral and a call wiwire which wire do I need to join in order to bypass the stat completely and prove its either working or not

 

[Killy Bing]

Live and call, the neutral is for the anticipator. That will put it as if its closed circuit or calling for heat if you prefer

 

[Reg Man]

Firstly you require something like a Multimeter or similar. You need to do a resistance test with the power off, across the contacts with the stat calling for heat then not calling for heat to see if the circuit opens or closes on the room thermostat. If it is an open circuit on both tests you then know that the stat is stuck open and not switching.

 

[beesley121]

Thanks. The stat is fine now. Just gotta see why heating only isnt firing up on 3 port valve even though 3 port valve moves

 

[Ermintrude]

If it worked before and don't now I would suggest its the microswitch?

 

[Inverness]

Can some one explain the advantages of a room stat?

as i find it hard to see the difference between a trv and a room stat.

My boss hates room stats and always just has trv's through the homes of installations we do. I question him and ask why not put a room stat, he replies he sees no point. Sines I'm only in my 1st year I've tryed to research myself but I tell him that a room stat switches the boiler off once temperature is reached where trv's stop the flow but the boiler still runs so you would manually have to switch it off I less it is on the timed settings.

i don't have that much knowledge in this as I'm only in my 1st year svq3 in plumbing.

id be very much gratefully if someone can explain in to me so I can then turn round and tell my boss. I already told him it's a regulation in all new installation a room stat to be fitted to any boiler.

 

[townfanjon]

No room stat !!! And he's teaching lol, very simply .....
a trv just turns the rad off into the room it serves
a room stat turns the boiler off

 

[Inverness]

He did say that there's a stat already inside boilers to know to turn off when reached temperature? My boss is clever guy. He has lpg tickets, gas safe, oftec, unvented, svq3.

so I'm kinda stuck in knowing whats best practise.

 

[julesverne]

Your boss is lazy stupid or both. A room thermostat will regulate the temp of the house as a whole, so when it reaches temp,it will shut the boiler down thus saving gas and lower bills for customer. The internal stat in boiler will just regulates the temperature of the water running through the boiler so if its set to max it run all day until switched off wasting gas and costing adding money to gas bills. trvs do a sort of job of regulating the temp in each room. But from experience the cheap,ones are absolute rubbish and most people just have them either whacked to max or zero and never in between.

Its a bit of a simplistic way of saying. Its a lot more technical than that and your employer should be able to describe it. If he does indeed have those gas tickets.

 

[leethegasman]

A room stat is also known as a boiler interlock so it turns off the heating demand electrically when the area that it is installed in reaches the set temperature.There should also be lock shield valves installed to the radiator in the room where the room thermostat has been installed non condensing system 11 degree temp difference over radiator.condensing system 20 degree temp difference over radiator.A correctly designed system in reality should heat up and cool down at the same rate in every room in reality this does not happen.The other reason I was told a room stat was needed one its in the building regs the other it stop the boiler cycling (coming on and off with the boiler stat)so prematurely wears out the pcb if the boiler has one that is, as relays etc within the board have operated more times over the same period hope that makes sense.
Also with lock shield valves install your system is always open circuit but if the system has pump over run you will need to install a auto bypass valve 100 per cent if using two port valves,if using three port valve installers differ on this one as the valve will be open circuit at all times ?
I'm sure there will be a few more reasons as we have all had different work experiences but this is my under standing hope this helps you.

 

[smtplumbing]

check the British standards about room stats

 

[julesverne]

so I'm kinda stuck in knowing whats best practise.

Best practice and common sense is they need fitting.

 

[Inverness]

Thank you very much. Looking forward tomorrow morning to buffle him with my knowledge. Ha ha

can you explain what you mean by non condensing system 11?

 

[julesverne]

There not even hard to fit

 

[smtplumbing]

some are wireless

 

[leethegasman]

Thank you very much. Looking forward tomorrow morning to buffle him with my knowledge. Ha ha

can you explain what you mean by non condensing system 11?

Older type appliances that you are most possibly used to taking out they don't have the over flow pipe coming out of them these types of systems would have been designed for 10 degree heat loss over the boiler and 1 degree for loss over system pipe work,condensing boilers ideally should have 20 degree loss over boiler 1 degree for system pipe work the reason is so there is a bigger temperature difference so in theory should condense more giving you greater efficiency.

 

[Inverness]

But having a room stat it saves money by switching the boiler off until the temperature drops. But for the boiler to start up again wouldn't it cost more it's like starting and stoping a car engine it wastes more fuel?
Yeah trv's regulate the flow but doesn't switch boiler off but the heat that's getting pumped around after all trv's have reached ideal temp the auto by pass kicks in and the boiler won't need so much fuel to pre heat the exsiting flow that's getting pumped around the auto bypass valve.

I find it hard to explain as I don't have yet proper words for what I mean.

 

[Reg Man]

Its not like a car engine. Agar engine needs to warm up to ne efficient a boiler does not.

 

[Dotty]

But having a room stat it saves money by switching the boiler off until the temperature drops. But for the boiler to start up again wouldn't it cost more it's like starting and stoping a car engine it wastes more fuel?
Yeah trv's regulate the flow but doesn't switch boiler off but the heat that's getting pumped around after all trv's have reached ideal temp the auto by pass kicks in and the boiler won't need so much fuel to pre heat the exsiting flow that's getting pumped around the auto bypass valve.

I find it hard to explain as I don't have yet proper words for what I mean.

You're looking at it from the wrong angle as far as efficiencies are concerned. If the boiler has the room stat installed then it'll turn off once the stat's satisfied. But if there's only the boiler stat, trv's and, hopefully, a bypass then the boiler is going to keep plumping away regardless of whether or not the trv's have closed down. This is a waste of energy and also increases head pressure on the pump and reduces the life of that.

And regardless of your employers personal opinion, he's in contravention of part L of the building regs.

 

[leethegasman]

But having a room stat it saves money by switching the boiler off until the temperature drops. But for the boiler to start up again wouldn't it cost more it's like starting and stoping a car engine it wastes more fuel?
Yeah trv's regulate the flow but doesn't switch boiler off but the heat that's getting pumped around after all trv's have reached ideal temp the auto by pass kicks in and the boiler won't need so much fuel to pre heat the exsiting flow that's getting pumped around the auto bypass valve.

I find it hard to explain as I don't have yet proper words for what I mean.

All a trv does is to close down and let less water in to radiator so makes the room more comfortable and saves gas.
All a bypass does is opens when you have a closed circuit eg zone valve closed or system with all trv closed down so the boiler can lose the heat, when boiler stat or room stat is satisfied the boiler shuts down and the pump Carrys on running some times for a set period of time eg 3mins or until a stat within the boiler is happy with the temperature of the boiler (depends on make of boiler)
It's not really like stopping and starting a car, yes when your system has been off for a while it will take more Enagy to raise the system water temperature from say 20degree to 82degree ,but when your say in a four hour timed heating period your system temperature will be warm so will not use as much Enagy to get back to the next cycle.

 

[stevetheplumber]

ask your teacher what he puts when the benchmark asks is an interlock fitted,if he puts no then further down the page it asks if it been fitted to part l to which he should also put no

 

[IDCHAPPY]

Best practice and common sense is they need fitting.

This^
Odd for someone who's been in the industry as long (i presume) as your gaffer, not to give a hoot about room stats :$

 

[Reg Man]

But having a room stat it saves money by switching the boiler off until the temperature drops. But for the boiler to start up again wouldn't it cost more it's like starting and stoping a car engine it wastes more fuel?
Yeah trv's regulate the flow but doesn't switch boiler off but the heat that's getting pumped around after all trv's have reached ideal temp the auto by pass kicks in and the boiler won't need so much fuel to pre heat the exsiting flow that's getting pumped around the auto bypass valve.

I find it hard to explain as I don't have yet proper words for what I mean.

Why don't you just trust the experts who write the national standards and work closely with heating manufacturers to establish the most efficient systems. All say room stat zone valve and boiler interlock.

 

[Inverness]

I explained to my boss about room stats how they will switch the boiler off once temperature is reached. He replied high limited stat inside the boiler will build up temperature and will switch boiler off if you have trv's throughout the house? When explained that a room state turns its self off once temperature is reached he said so does the stat inside the boiler if you were to have all trv's

If this is the case all boilers come with boiler interlock? And does this apply to all types of houses?
Im confused...
I'm i correct that a room stat is mainly to warm the biggest area and coldest part of the house and once set it can reach temperature and then switches itself off saving you money?

Where a trv controls the flow and can't switch the boiler off it will keep on running until you manually turn the boiler off or it's out of its programmer timer slot. And when all trv's have reached temperature the pumped water circulates between the automatic by pass and boiler. Where the boiler is still running and wasting money the difference between a room stat once it's reach temperature it switches it's self off that then saves you money on fuel and less wear and tear on pump.

please can someone help me..

 

[tamz]

To save a lot of typing read this, print of pages 9 and 10 and give it to your boss on Monday. http://www.centralheating.co.uk/sys...s/0000/0157/CE51_CHeSS_WEB_FINAL_JULY_081.pdf
And if your Inverness name means you live in Scotland read from page 35 here cos we don't have Part anything up here
http://www.scotland.gov.uk/Resource/0045/00459729.pdf