Intergas boiler

er...er...er a bit like dismissing a boiler because of a diverter valve that might go wrong or an automatic air vent? Or a cast iron OF boiler that is incredibly reliable but works at 50% efficiency? I dismiss it not because of reliability but safety.

I used bithermic heat exchanger boilers many times in the past and have seen the possibilities.

The thing is most boilers are installed into existing systems where the rads were designed for their certified temperature flow in of 75 degrees not 80. If the weather is extreme then that temperature is what the radiators will require to heat the property (many new build rads are sized to minimum also and most of those systems are certainly not weather comped even now).

If the heating system requires water at high temperature to keep the customer warm that is what it will be set to then you have the domestic hot water circuit at whatever temp the boiler stat is set to, there's a comparatively large quantity of it in the IG and it can be set to 90 degrees!!

A blending valve is not particularly cheap, certainly not low maintenance and adds rather to the number of moving parts.

The boiler has merits and is loved by many who know how to fit them, it will not always be nor operated by those who do not understand the possibilities.

Still the change from GAD to GAR last year will protect the installer giving separation between yourself and the customer if heaven forbid an untoward incident occurred. With the Directive the installers responsibility was to choose and install an appliance that could not endanger the end user by adjustment either deliberate or accidental. The GAR now places the responsibility for the same criteria on the manufacturer who must not place into the market in the EU any gas appliance that can be configured either deliberately or inadvertently to endanger the user. As this depends on the manufacturer's own risk assessment IG say it's an acceptable risk, I have a different opinion. I enjoyed your comment 'most users do not have the setpoint at a high level' these are not the people who are the concern.

There are installers who I respect enormously who fit almost nothing but IG and I have recommended old customers of mine to them knowing the boiler will be installed and the user instructed in the use. The electronics and control possibilities I'm told are exceptional but I would not want one in my own or a family members house particularly if children are present.

As for saving the planet, get real.

Tadlad's earlier post regarding hot water temperature control shows he does not understand the relevance.

Not going to get into a heated debate although you could mention that you work for a competitor but do you really still tell installers to set the flow temp to 80 degrees on Vokeras?

Most boilers I attend set up by quality installers have a flow temp of somewhere around 65/68 degrees. The days of an 11 degree delta went out when steamers were made compulsory and systems are specced on a max of 70 degree flow to ensure the return is low enough to condense.

How efficient are Vokeras when run at an 80 degree flow temp?
 
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OMG you are conflating a problem with Intergas Boilers and some scenario that a jet of boiling water scalds some kid. I am not an installer I actually work at the sharp end of the NHS and I have never seen a central heating boiler related burn ever. Seen plenty of other ways kids have been hurt tho. Not heard of it in my extensive research either. By your logic any boiler is a deathtrap to some unsuspecting child.

Actually he has a point although wildly exaggerated. If the boiler flow temperature is set to 90 degrees the first 'slug' of water out of the taps will not be far off that.

That's an installation issue not the boilers fault. With modern insulation and windows the flow should not need to be set much more than about 65 degrees which will give an initial water temp of about 55 degrees C

Modern controls are all aimed at keeping the flow temp as low as possible. Once up to temp the rads will be at less than 40 degrees...

By the same token with the 80 degree plus flow temp that VC is recommending how long would it take to get serious burns when leaning against a radiator?
 
That's an installation issue not the boilers fault. With modern insulation and windows the flow should not need to be set much more than about 65 degrees which will give an initial water temp of about 55 degrees C

If the heat exchanger is running CH at 65°C then the water in the DHW coil in the heat exchange will also the very close to 65°C. Opening a hot water tap will release that slug of hot water out to the tap before cold water from the mains cools the heat exchanger.
 
It won't be at 65 degrees due to the layout of the coils in the hex.

I've tested it personally have you?
 
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It won't be at 65 degrees due to the layout of the coils in the hex.

Yes I know the DHW coil is further from the flames than the CH coil but the thermal gradient across the heat exchanger is not that great when CH has been running at 65°C for a while.

I've tested it personally have you?

So how hot was it. How far from the boiler along the hot water pipe did you place the temperature sensor ?
 
Yes I know the DHW coil is further from the flames than the CH coil but the thermal gradient across the heat exchanger is not that great when CH has been running at 65°C for a while.



So how hot was it. How far from the boiler along the hot water pipe did you place the temperature sensor ?


Perhaps you should actually read my earlier post.......

And the data was taken directly from the temp sensor on the boiler
 
need to be set much more than about 65 degrees which will give an initial water temp of about 55 degrees C

How does that happen.... a 10° difference across the solid aluminum heat exchanger. I can accept that heat removed from the heat exchanger by water flowing in the CH coil will create a shallow gradient but if CH is at 65°C then the heat exchanger will be hotter than 65°C.

And the data was taken directly from the temp sensor on the boiler

Directly from the sensor or via the boiler's processing to a display on the boiler.

The tests I am aware of used PT100 thermometers to get accurate readings of water ( pipe surface ) temperatures.
 
Tadlad's earlier post regarding hot water temperature control shows he does not understand the relevance.

Read more: https://www.diynot.com/diy/threads/intergas-boiler.521289/page-3#ixzz5mhIG5217

OMG you are conflating a problem with Intergas Boilers and some scenario that a jet of boiling water scalds some kid. I am not an installer I actually work at the sharp end of the NHS and I have never seen a central heating boiler related burn ever. Seen plenty of other ways kids have been hurt tho. Not heard of it in my extensive research either. By your logic any boiler is a deathtrap to some unsuspecting child.

I am an installer, I have installed bi-thermic heat exchangers, I've been aware of the problem. If you've never seen it it can't exist I guess. It's your grandchild not mine.

"Hot water set at 65 Degrees and warms up gently with the eco function off that preheats the exchanger." suggests otherwise
 
Not going to get into a heated debate although you could mention that you work for a competitor but do you really still tell installers to set the flow temp to 80 degrees on Vokeras?

Most boilers I attend set up by quality installers have a flow temp of somewhere around 65/68 degrees. The days of an 11 degree delta went out when steamers were made compulsory and systems are specced on a max of 70 degree flow to ensure the return is low enough to condense.

How efficient are Vokeras when run at an 80 degree flow temp?


I thought I was fair in my opinions, I didn't mention I worked for a boiler manufacturer as I wasn't recommending our product or in fact any product, just expressing an opinion. Crumbs, I even said I've recommended certain installers who fit Intergas to my old customers because I know they'll be put in by someone who knows what they're doing.

I did not mention 80 degrees, I said rad outputs were certified with a flow at 75 degrees and if they're operated cooler the output to the room will be less so some users will turn the temperature of the heating supply up and that's where a problem can arise.

Vokera boilers as you well know have a plate exchanger a diverter valve and a primary flow and a hot water thermistor all of which are used to ensure a DHW below 60 degrees as the heating circuit is kept separate, when they are parallel the separation is only made after hot water in the domestic section is exhausted, hopefully at a safe temperature.

Generally Vokera's are very efficient at any temperature because of the design of the hex and you'd be looking at a differential of between 3 degrees to 14 degrees flue to return depending on whether it is an economy or commercial product. This very morning I was looking at a consistent dfferential of 6 degrees on a domestic evolve flue to return on maximum output. That's what tells the installer how much heat is leaving the boiler through the flue but because of the test rig I couldn't raise the flow to above 60.

If the boiler can be set to 90 degrees output heating, and eco mentioned the hot water can too but I don't know whether I read that wrong, I don't think that is an installer fault.

When are we going to meet, I'd like a good chat, are you going to Installer or there's loads of coffee shops near Colney?
 
Tadlad's earlier post regarding hot water temperature control shows he does not understand the relevance.

Read more: https://www.diynot.com/diy/threads/intergas-boiler.521289/page-3#ixzz5mhIG5217

OMG you are conflating a problem with Intergas Boilers and some scenario that a jet of boiling water scalds some kid. I am not an installer I actually work at the sharp end of the NHS and I have never seen a central heating boiler related burn ever. Seen plenty of other ways kids have been hurt tho. Not heard of it in my extensive research either. By your logic any boiler is a deathtrap to some unsuspecting child.

burn.jpg


This was NOT from an Intergas or combi boiler set too high but simply the burn you said didn't exist as you've not seen it.

Hot water damage to human tissue; the regs were tightened regarding hot water supply a few years ago after two deaths of children and some serious eventually fatal burns to the elderly who cannot react quickly enough to get their bodies out of seriously hot water.

See you at the sharp end.
 
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Hot water damage to human tissue; t

There is also the harm that cold water shock can do. Being suddenly and un-expected immersed in cold water can be fatal. As in a shower when the boiler shuts down and hot water becomes cold without warning.

The sudden cooling of the skin by cold water causes an involuntary gasp for breath. Breathing rates can change uncontrollably, sometimes increasing as much as tenfold.

Cold water shock causes the blood vessels in the skin to close, which increases the resistance of blood flow. Heart rate is also increased. As a result the heart has to work harder and your blood pressure goes up. Cold water shock can therefore cause heart attacks, even in the relatively young and healthy.
 
I could summarize this latter debate by reminding everyone that there have been lots of bithermic heat exchanger boilers launched since the birth of the combi.

Models from Ferroli, Potterton and Worcester I have worked on, and now I hear that Vokera also had one.

All these manufacturers eventually dropped their bithermic designs and went back to plate heat exchangers. Limescale (not an issue in Holland) and dangerously hot slugs of water were their downfall.

Intergas say that the flow temperature of the heating should be reduced and this mitigates the issue.

The issue is that many of their boilers are being fitted in older UK housing stock where the radiators were sized appropriately for a Central Heating flow of up to 75-80c. I doubt many Intergas customers have had their radiators changed to increase their surface area; therefore on the coldest days a 60c flow temp will leave them cold.

I don’t see many posts on here advocating to potentially clueless internet customers doing ‘research ‘ (eg: not heating professionals) that they may have to upsize their radiators.

And here is the rub. If it were advertised as a boiler with less moving parts but in older retrofits you might need to change the radiators- they wouldn’t sell many.
 
I could summarize this latter debate by reminding everyone that there have been lots of bithermic heat exchanger boilers launched since the birth of the combi.

Models from Ferroli, Potterton and Worcester I have worked on, and now I hear that Vokera also had one.

All these manufacturers eventually dropped their bithermic designs and went back to plate heat exchangers. Limescale (not an issue in Holland) and dangerously hot slugs of water were their downfall.

Intergas say that the flow temperature of the heating should be reduced and this mitigates the issue.

The issue is that many of their boilers are being fitted in older UK housing stock where the radiators were sized appropriately for a Central Heating flow of up to 75-80c. I doubt many Intergas customers have had their radiators changed to increase their surface area; therefore on the coldest days a 60c flow temp will leave them cold.

I don’t see many posts on here advocating to potentially clueless internet customers doing ‘research ‘ (eg: not heating professionals) that they may have to upsize their radiators.

And here is the rub. If it were advertised as a boiler with less moving parts but in older retrofits you might need to change the radiators- they wouldn’t sell many.

Interesting. So are you saying you regularly leave combi boilers with a set temp of 80 degrees. How do you manage that and stay boiler plus compliant?

Can no one in your area afford double glazing?

I wouldn't want your clients heating bills - some of us have moved on from the 70's :mrgreen:
 
Can no one in your area afford double glazing?

Even with double glazing the existing radiators may be too small to provide adequate heat when CH water temperature is reduced down to 60°C

When heating was installed the radiators would have been sized for 80°C water and double glazing in place.

Perhaps an upgrade to triple glazing is the solution to preventing hazardous hot slugs in the domestic hot water supply from certain makes of combi boilers.
 
Radiators can be run at any temperature it's just the catalogue output figures for a particular size are determined with a flow of 75 and a return of 65 in a room at 20 degrees so if the heat loss calculation was correct, seldom the case, that's the output you'd expect from it. Lower temperature you'll get less output, higher more.

If you're a fan of condensing try to run chilled water through them at below ambient room temp and harvest the latent heat given off when condensation forms on them; you'll need it as the room will be cooler due to the transfer of sensible heat.

Not making a point it's all a matter of perspective.

On a separate note a program called skylab on BBC iplayer was great at illustrating latent heat. By flying an airship through clouds slowly boffins were able to take readings of weight and temperature of clouds, how the water changes from vapour to ice to liquid. A small cloud weighed 4 tons and a larger one at higher altitude if the vapour was condensed contained energy equivalent to the Hiroshima bomb.

I think it was over a hundred trillion tons of water above our heads in the air at any time.

Off topic but fascinating to me, I would recommend it. My head has been in the clouds more than usual since watching it.
 

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