Boiler replacement quote

southcoastrgi

Slothy wrote: »

I received a wiring diagram from Viessmann that does clearly state that for a 3rd party unvented DHW cylinder, a motorised cut-out valve should be fitted (not required for their own cylinders, however).

Thank you OP I do so hate it when I'm proved right, so like I originally said the 2nd guy to quote didn't know what he was doing & it could have been dangerous to remove the zone valve, just goes to prove a little bit of knowledge is a dangerous thing, so maybe some people need to look into a few more things before THEY spout misinformed rubbish. :rotfl:

keystone

Handbags anyone?

Cheers

gas4you

Decent unvented HW cylinders have a dry pocket for a temperature sensor to be inserted to give a constant reading back to the controls so the boiler knows exactly what temp to produce for heating the hot water efficiently.

Southcoast, the OP has been talking about a traditional system with a hot water cylinder, yet you post info that is only relevant for a combi system, or one that has no hot water side.

Who is the idiot?

I don't fit Sime as a rule, I have done with the new boilers, and had absolutely no problems.

I fit Broag as the boiler of choice. The fact that I've had a contract with them and carry out warranty repairs, when asked, for them in my area has nothing to do with my choice of what to fit.

The motorised valve that acts as the thermal cut out would usually be wired to the hot water cylinder, but as rules and regs have/are changing, the necessity for this to act as a safety valve is now becoming obsolete.

Most manufacturers are now claiming that as the boiler has it's standard thermostat and an overheat protection that cuts off the boiler at around 90c, there is no way the cylinder could get hotter than 90C.

Try to keep up Southcoast, or stick to what you know best, old fashioned gravity primary systems.

southcoastrgi

I am not & have never talked about a combi as the op has a megaflow so why would he have a combi, if you fit Remeha then you know don't you about their weather comp?

i totally fail to see your reasoning with regard to weather comp only working on a combi it will work fine on a heat only boiler, if the manufacturers are as you say why does neally every unvented cylinder still come with a zone valve & pray tell unless you fit a pointless & more expensive 4 pipe boiler with no zone valve how are you suppost to control it. unfortunately for you due to the op finding out that the Visseman really isn't compartable with his megaflow I think your credibility on this thread is somewhat dented,

just as a side note i have to re-do my G3 unvented in a few months & i will ask about the 4 pipe boilers & your points with regard to removing the zone valve & if i am wrong then i will say.

Slothy

Southcoastrgi will probably get a chuckle out of this: just found an article in the newspaper about the firm who provided quote nr 2: http://www.dailyrecord.co.uk/news/scottish-news/rod-mcdougall-crashes-company-1268878

Guess that's them off my list. Remeha have informed me that my local PTS is their stockist, so I'll see if they have any Remeha installer recommendations.

I did have a look at Worcester Bosch controls, as quote nr 1 is the only one left as a serious contender. However, I notice that their dual-channel timer requires an internal diverter valve to be fitted to their system boiler, turning it into a... 4 pipe system

Slothy

gas4you wrote: »

Decent unvented HW cylinders have a dry pocket for a temperature sensor to be inserted to give a constant reading back to the controls so the boiler knows exactly what temp to produce for heating the hot water efficiently.

I contact Heatrae about whether a sensor can be added to the cylinder. They suggest that the backup electric immersion heater can be removed (permanently) and its pocket used for a sensor. They had no alternative solutions. The cylinder is probably 5 years old, so not sure if newer models are more sensibly designed with sensor pocket.

southcoastrgi

Op thank you for the link yes I did smile, not because of the customers that are now left high & dry which is terrible but because you had a lucky escape, a mid postion valve does exactly the same thing as two zone valves in it's operation obv the wiring is slightly different as you have two valves instead of one but in principle they are the same, most mid postion valves will come to rest in the hot water open postion & if there was a fault with it & the boiler continued to fire then the cylinder would continue to heat which is why you fit a two port zone valve to the cylinder as a thermal cut out, I think you will find with the wb that the mid postion valve could be changed for two zone valves which would be suitable for you, there is some confusion here just by fitting a mid postion valve anywhere in the system this doesn't make it a four pipe system it's still only a two pipe system the heating & cylinder returns will be linked together somewhere before they go back to the boiler, so does this make it a three pipe system ? Who knows lol, As Fergal Sharky once sang, a good installer these days is hard to find.

Good luck.

andy.m_2

Southcoast do you service installations?
I kind of admire your no nonsence no BS approach and while you may be a little blunt, you do warn of that fact in your sig!

southcoastrgi

Thank you Andy, I am always very polite & will try to explain things to my customers so they can understand as you can see if you look at some of my other postings on other threads, if I don't know the answer to an OP's thread then I won't answer or post on it as it just leads to the op getting confused, however in the same vain I really don't appreciate people slagging me off & tell me I'm wrong when I know I'm not as this thread has proved, if I have got something wrong then I will hold my hands up & admit it, we all make mistakes & no one knows everything & yes rules, regs & products change & I do try to keep up with the latest things even though I may not use them, I have heard very good reports of Vissman boilers although I have never fitted one, but sometimes people come out with totally pointless things that are destined to fail eg Barlo rads (now Quinn) very good rads & rarely had a prob with them & then they decided to make a boiler what a disaster that was they were rubbish always breaking down (although I not sure that they weren't just a re-badged model from someone else), so sometimes things are good ie Gun Wharf & other things are either not fit for purpose or are so over engineered that they are pointless.

gas4you

Yes I know all unvented cylinders come with a 2 port, but the boiler manufacturers are adamant that it is unnecessary.

They know one hell of a lot more than me.

Yes I know Broag and their WC, but unless I'm forced to fit WC by a customer, I wont entertain it.

It's a waste of time IMO and the savings are minuscule.

Now, however, that Broag are supplying a modulating room stat with the combi boiler things may get better.

You could call an unvented cylinder manufacturer and ask them if the discharge is allowed to be made to a soil stack via a HEPv0 trap, and they will say know, but in reality it is allowed and done most of the time these days, especially in new build.

I have never said WC won't work with a standard boiler, what I did say is that by some means or other, the boiler would have to be told when it is supplying the demand to heat the HW cylinder so that it could over ride the WC and increase the flow temperature.