A boiler with a 22m cold/hot feed?

[Deleted member 137318]

I have just had the lead mains pipe from the street to my house replaced - partly on a quest to improve mains pressure and partly because of the 'lead' aspect. Thames Water incidentially said that I have nothing to worry about because the lead mains pipe would be coated with limescale by now so the chance of injesting lead was neglible (so when a large corporate says don't worry I tend to worry).

Anyway, pipe replaced, the pressure to my new stopcock is now good - well better than it was anyway, (I managed to soak the ceiling just by a cursory quarter turn on the tap so I was happy).

I now need to replace my boiler and wanted to continue this new found pressure right to my bath tub so I was wondering if there are any manufacturers that make boilers with 22mm cold & hot feed. All I have seen so far are boilers with 15mm supplies. Is this possible or am I going to have to reduce it down to 15mm and then back out to 22mm at the bath? Ideally I like it to be a combi boiler as well but understand that I might be asking too much of one boiler

 

[Andygasman2010]

I'm not aware of any domestic sized combis like that. Have you thought about getting an unvented cylinder?

 

[nickso]

problem with that is a 22mm pipe holds far more water than a 15mm, (well duh ) but that means the combi will have to heat that extra capacity before you get hot out of the tap.

unless there is another reason why you feel you need to do this, don't.

 

[rojaca]

Flow rates on combis would mean that there would be no benefit of increasing pipework to 22mm.
Additionally, as above, max run from boiler to outlet reduced when using 22mm to restrict qty water wasted.

 

[Homesafe]

I'm not aware of any domestic sized combis like that. Have you thought about getting an unvented cylinder?

I agree with Andy, get an unvented if you want good flow at multiple outlets. Putting a 22mm feed into and upto the taps will not get you the required performance.
The boiler can only heat a fixed amount of water at a certain flow rate going through it, so bigger bore pipe is not going to change that.
Maybe someone will tell me different, who knows .

 

[tamz]

As far as i know this is the only combi with 22mm connections for hot and cold

http://www.discountedheating.co.uk/shop/acatalog/Grant_Vortex_36_HE_Combi_Oil_Boiler.html

Wrong fuel tho

 

[gas4you]

The Baxi 130HE was the only boiler that I can remember that had a 22mm outlet for HW.

Can't think of any now though.

 

[Deleted member 137318]

Thanks for all your responses and ideas. I would prefer to stick with the open vented system that's already in place - if possible. I guess the increased pressure may help (even via 15mm pipe)

 

[gigz]

If you have an open vented system the new mains will only improve any taps connected directly to the mains and fill times for cisterns and tanks, what system do you have currently ? You may need to lift your cws tank or hot outlet/cold inlet could be partially blocked (lime etc)

 

[Bon]

Thanks for all your responses and ideas. I would prefer to stick with the open vented system that's already in place - if possible. I guess the increased pressure may help (even via 15mm pipe)

If it's an open-vented system with F&E cistern above a cylinder then the size of the boiler pipework won't make a bean of difference to your hot/cold water flow.

Your new incoming cold water pipework won't improve your hot water flow either as the cold feed a cistern which then gravity flows to your taps. To improve your hot water flow rate you need to, as said, raise your F&E cistern and increase the dia of the pipework from the cistern to the cylinder and from the cylinder to the taps.

 

[Deleted member 137318]

Actually my current setup is something of a dogs dinner:

There are no tanks in the house anywhere.I have a boiler in the kitchen that provides mains fed hot water throughout the house (is it called instantaneous?) and another in the garage that provides for the central heating. The central heating one is open vented fed from the loft by a header tank. Both are ageing and not condenser types so I imagined changing the central heating boiler for a combi to serve both hot water on demand (like the kitchen one) and run the central heating as well. Then I can discard the kitchen one - freeing up space. Am I making sense??

I have a scrappage voucher with a few weeks left on it so I wanted to take advantage and upgrade to the one boiler - preferably keeping the flow rate of hot water quite high (hence the original subject line of this thread).

Thanks again everyone - really appreciate this good advice

 

[Andygasman2010]

How many baths/showers do you have?

 

[Bon]

Actually my current setup is something of a dogs dinner:

There are no tanks in the house anywhere.I have a boiler in the kitchen that provides mains fed hot water throughout the house (is it called instantaneous?) and another in the garage that provides for the central heating. The central heating one is open vented fed from the loft by a header tank. Both are ageing and not condenser types so I imagined changing the central heating boiler for a combi to serve both hot water on demand (like the kitchen one) and run the central heating as well. Then I can discard the kitchen one - freeing up space. Am I making sense??

I have a scrappage voucher with a few weeks left on it so I wanted to take advantage and upgrade to the one boiler - preferably keeping the flow rate of hot water quite high (hence the original subject line of this thread).

Thanks again everyone - really appreciate this good advice

Ahh, now it makes sense!

The only problem with a combi is that if you're in the shower and someone turns a hot tap on in the kitchen, you'll know about it!!

My advice would be to scrap the water heater in the kitchen and get a new system boiler in the garage, along with an unvented water heater.

This set-up will give you a large volume of stored hot water that will be delivered at mains pressure to several taps at once.

The other option is a storage combi (I think Vaillant do them) which is, as the name suggests, a combi boiler with a small storage vessel built in which goes a long way to overcoming the dips in hot water flow that plague combi installations and gives a decent continuous flow of water.

 

[Deleted member 137318]

How many baths/showers do you have?

I have 2 showers and 1 bath

 

[Deleted member 137318]

Actually my current setup is something of a dogs dinner:

There are no tanks in the house anywhere.I have a boiler in the kitchen that provides mains fed hot water throughout the house (is it called instantaneous?) and another in the garage that provides for the central heating. The central heating one is open vented fed from the loft by a header tank. Both are ageing and not condenser types so I imagined changing the central heating boiler for a combi to serve both hot water on demand (like the kitchen one) and run the central heating as well. Then I can discard the kitchen one - freeing up space. Am I making sense??

I have a scrappage voucher with a few weeks left on it so I wanted to take advantage and upgrade to the one boiler - preferably keeping the flow rate of hot water quite high (hence the original subject line of this thread).

Thanks again everyone - really appreciate this good advice

Ahh, now it makes sense!

The only problem with a combi is that if you're in the shower and someone turns a hot tap on in the kitchen, you'll know about it!!

My advice would be to scrap the water heater in the kitchen and get a new system boiler in the garage, along with an unvented water heater.

This set-up will give you a large volume of stored hot water that will be delivered at mains pressure to several taps at once.

The other option is a storage combi (I think Vaillant do them) which is, as the name suggests, a combi boiler with a small storage vessel built in which goes a long way to overcoming the dips in hot water flow that plague combi installations and gives a decent continuous flow of water.

I really like the idea of the storage combi - sounds like the answer. What sort of footprint are we looking at and what model would be good for a standard 4 bed semi with a family of 4 bathing/showering once a day? I was told that Vailant was 'the boiler to have' by someone I trust.