Best Combi

[durhamplumber]

Many of us that repair boilers have tales of boilers being replaced due to slow parts availability.

I have umpteen tales of same day boiler repairs.

 

[fixitflav]

Lol...Thanks for the tips but I have repaired boilers etc for a while..If a combi goes wrong...The vast majority are probably repaired same day or v shortly afterward..IMHO having a backup immersion makes as much sense as having a back up car..Managing without hot water for a day in 10years but planning ones heating system around that possibility is nuts.

That might be an argument if standby immersion heater were the only reason against having a combi. But there are plenty of pros and cons with both, which need weighing up before making the choice.

 

[bernardgreen]

IMHO having a backup immersion makes as much sense as having a back up car.

I have a "back up" car. It is a taxi. ( rhymes with Baxi )

Managing without hot water for a day

can be a serious problem for some people

planning ones heating system around that possibility is nuts.

It could also be seen as being nuts to install a system that wastes gas. All boilers waste a bit of gas when they fire up and shut down, A combi fires up every time a hot tap is turned on, this happens many times a day. Other boilers maybe only fire up 4 or 5 times a day.

 

[RobGra]

Lol...Thanks for the tips but I have repaired boilers etc for a while..If a combi goes wrong...The vast majority are probably repaired same day or v shortly afterward..IMHO having a backup immersion makes as much sense as having a back up car..Managing without hot water for a day in 10years but planning ones heating system around that possibility is nuts.

Thanks for all the opinions. I guess there are many pros and cons either way. Of course the benefit of being able to havev an immerser as back up is great, however, the downside of having a tank system is the increased risk of legionella, and particularly in SNP run Scotland where you now need to conduct legionella risk asessments for rental properties that have attic tanks - and trust me, this is a bloody nightmare! Its only a matter of time before this is extended to all properties!

As far as the combi route is concerned, my only fear is pressure drop or leakage from the existing pipework, which seems to be a curse with combi systems.

Incidentally, my pigging boiler hasn't locked out for 2 days now, which is infuriating me!

 

[Gasguru]

Legionella...the cylinder water is stored at 60 degrees.
I can tell you endless stories of botched combi installs with unbalanced bath taps/showers that shove hot water up to the redundant cold cistern...now there's a legionella risk.

 

[charliegolf]

I would say anything but a combi.

Not what he/she asked.

 

[Harry Bloomfield]

Thanks for all the opinions. I guess there are many pros and cons either way. Of course the benefit of being able to havev an immerser as back up is great, however, the downside of having a tank system is the increased risk of legionella, and particularly in SNP run Scotland where you now need to conduct legionella risk asessments for rental properties that have attic tanks - and trust me, this is a bloody nightmare! Its only a matter of time before this is extended to all properties!

Do one risk assessment then unless something in the property changes, it will be a rubber stamp job each time. Modern control systems have the ability to bring the stored water up to 60C once per week to combat the Legionella anyway.

Being without adequate hot water and heat in winter is no fun at all, even for a short period. I'm an owner occupier and I have a series of back up plans to cover for failures, including immersion heater, gas fire, spare electric heaters and spare parts for my heating system. In 40 years, we have only been without heating for a few days when the boiler failed suddenly and completely, needing complete replacement - other failures have been sorted quickly within hours, by me.

An open vented facilitates back up plans and is usually cheaper to repair when it does go wrong. I also suspect they are much less troublesome anyway, if looked after even reasonably.

Installers push combi's simply because they are much simpler and less costly to install. When replacing an open vented with a combi, they can make good money on the copper scrap. Then even more on the return visits to fix the issues.

 

[RobGra]

Legionella...the cylinder water is stored at 60 degrees.

Yes, but not the CW storage tank which supplies the bathroom taps....

 

[RobGra]

Do one risk assessment then unless something in the property changes, it will be a rubber stamp job each time. Modern control systems have the ability to bring the stored water up to 60C once per week to combat the Legionella anyway.

Being without adequate hot water and heat in winter is no fun at all, even for a short period. I'm an owner occupier and I have a series of back up plans to cover for failures, including immersion heater, gas fire, spare electric heaters and spare parts for my heating system. In 40 years, we have only been without heating for a few days when the boiler failed suddenly and completely, needing complete replacement - other failures have been sorted quickly within hours, by me.

An open vented facilitates back up plans and is usually cheaper to repair when it does go wrong. I also suspect they are much less troublesome anyway, if looked after even reasonably.

Installers push combi's simply because they are much simpler and less costly to install. When replacing an open vented with a combi, they can make good money on the copper scrap. Then even more on the return visits to fix the issues.

Great idea, but incorrect im afraid. You must submit an accurate system drawing with all applications, along with instructions to tenants on how to disinfect any outlets.

 

[durhamplumber]

I can tell you endless stories of botched combi installs with

The anti combi force sure is strong in you...I can tell you endless stories of crap Gledhill units etc...

 

[Harry Bloomfield]

Yes, but not the CW storage tank which supplies the bathroom taps....

That is not a Legionella concern. It only breeds in warm water, hot water (>55C) kills it off.

 

[durhamplumber]

Installers push combi's simply because they are much simpler and less costly to install. When replacing an open vented with a combi, they can make good money on the copper scrap. Then even more on the return visits to fix the issues

All common misconceptions Harry.A longer install = more money for plumber.Most combis have 10year warranty so no money to be made on repairs....Scrap copper is not worth a fortune.etc.In many properties space is premium..Why have tanks etc if not required.

 

[durhamplumber]

Being without adequate hot water and heat in winter is no fun at all, even for a short period.

So keep a tank full of water hot for ten years in case it is needed for the odd day!?An immersion heater willnot provide CH if the boiler is off.

 

[Harry Bloomfield]

All common misconceptions Harry.A longer install = more money for plumber.Most combis have 10year warranty so no money to be made on repairs....Scrap copper is not worth a fortune.etc.In many properties space is premium..Why have tanks etc if not required.

Maybe, but every one I know (not many) who have moved from open vented to combi, have regretted it. Complaints of waiting for baths to fill and waiting for the hot water at the taps to actually become hot. Swapping from open to combi, is certainly a longer job, than just fitting a replacment boiler.

 

[Gasguru]

You gas registered durham?
Don't see you in the chamber.