Buffer cylinder for unvented

[muggles]

Put a blending valve on the DHW draw off and store water at approx 80C. Normally the boiler cuts in when the cylinder is one third exhausted. Add a flow switch to the cold feed to the cylinder, so when DHW is drawn off the boiler cuts in immediately, combining the boiler output and energy in the cylinder. Simple, by fitting a blending valve and a flow switch.

Just by adding the blending valve will bring excellent results. Store the water as hot as possible, 80-85C. Adding the flow switch would be even better.

Wow, so much stupid in one post

Unvented cylinder stats don't usually go above 65, much more than that and the safety overheat cutout will activate, so you'd have to swap it out for a non-approved type with no safety.

You're then bypassing the stat altogether with the flow switch, which is clearly unsafe. What happens if the switch jams on? The cylinder just gets hotter and hotter, potentially 90°C, or even hotter if it's an old boiler on with a dicky stat.

You're also using a huge amount of additional energy running the cylinder like this

 

[hard-work]

Not to mention bypassing the hysteresis of the cylinder stat to make the flow switch activate immediately. Heaven forbid that someone draws a few litres off for washing their hands and cause micro-firing of the boiler.

Not to mention too the crazy lack of efficiency running a boiler at 90 degrees, which is what you'd have to do to get the cylinder up to 80. Even at 90-degree flow, trying to get a cylinder to 85 would be pointlessly inefficient and the boiler will be cycling for hours trying to get over the last 5 - 8-degree hurdle.

This is, of course, assuming you can maintain G3 compliance; ignoring the obvious foolishness of running a cylinder so close to the safety devices cut in point as leave no margin for error.

Hard-On - you are such a moron it must be painful.

Our resident Plantpot comes in again on cue. Of course the flowswitch can override the cylidner thermostat. If you do not want nuisance firing of the boiler then have a by-pass around the flow switch with an inline restrictor. Adjust the inline restictor to the level you want the flowswitch to switch in. Simple. Now you know. You make me larf.

You can spend a fortune on a new cylinder or raise its temp and fit a blending valve saving a fortune. You make me larf. Positive engineering thought eludes most.

 

[Dan Robinson]

What a crock of bullschit. But as Dilalio said - it is somewhat entertaining.

I see you've only addressed part of the problem (in a very clunky and unnecessary way).

 

[hard-work]

Wow, so much stupid in one post

Unvented cylinder stats don't usually go above 65, much more than that and the safety overheat cutout will activate, so you'd have to swap it out for a non-approved type with no safety.

You're then bypassing the stat altogether with the flow switch, which is clearly unsafe. What happens if the switch jams on? The cylinder just gets hotter and hotter, potentially 90°C, or even hotter if it's an old boiler on with a dicky stat.

You're also using a huge amount of additional energy running the cylinder like this

Higher range stats are available.

By-passing the cylinder stat by the flow switch is not unsafe as it is only by passed when there is a substantial volume of hot water drawn off. When the draw-off stops the stat is then switched back in.

 

[muggles]

Higher range stats are available.

By-passing the cylinder stat by the flow switch is not unsafe as it is only by passed when there is a substantial volume of hot water drawn off. When the draw-off stops the stat is then switched back in.

There's a world of difference between "available" and "approved for use". I note you've conveniently forgotten to answer my query about what happens when the flow switch sticks on and you've overridden the safety system

 

[dilalio]

Higher range stats are available.

By-passing the cylinder stat by the flow switch is not unsafe as it is only by passed when there is a substantial volume of hot water drawn off. When the draw-off stops the stat is then switched back in.

So, contrary to your post below...

Look at the pressure and temperature controls on unvented cylinders. What could go wrong? Someone on another thread posted a vid of an unvented cylinder exploding.

. . You're now intimating that it's OK to bastardise the controls on a UV, thus contravening the stipulations, as set out in (the reasonably consistent) MI's of all UV manufacturers!

Brilliant .

 

[hard-work]

There's a world of difference between "available" and "approved for use". I note you've conveniently forgotten to answer my query about what happens when the flow switch sticks on and you've overridden the safety system

Don't you know the safety valves on an unvented cylinder?

 

[hard-work]

So, contrary to your post below...
. . You're now intimating that it's OK to bastardise the controls on a UV, thus contravening the stipulations, as set out in (the reasonably consistent) MI's of all UV manufacturers!
Brilliant .

No more dangerous to what they normally are.

 

[Dan Robinson]

Muppet.

 

[muggles]

Don't you know the safety valves on an unvented cylinder?

Yes, they're the last line of defence when all else has failed. They aren't there to cater for idiots putting unapproved thermostats on and overriding the other safety features

 

[hard-work]

to cater for idiots putting unapproved thermostats

In other words you have not a clue unable to think for yourself, only going on Manufacturers manuals. Pretty sad.

 

[dilalio]

In other words you have not a clue unable to think for yourself, only going on Manufacturers manuals. Pretty sad.

"Did you have access to, and read the manufacturer's installation instructions?"

"Yes"

"Did you follow those instructions, as set out in the installation manual?"

"No, but..."

"Is this your signature at the bottom of the Installation Certificate, known as the Benchmark?"

"Yes, but..."

"No further questions Your Honour"

 

[bernardgreen]

"Did you follow those instructions, as set out in the installation manual?"

"No, but..."

the "but" might have been followed by a description of an error or ommission in the manufacturer's instruction which the installer had correctly identified as creating a hazard or harm greater than the harm he or she is charged with causing.

 

[dilalio]

the "but" might have been followed by a description of an error or ommission in the manufacturer's instruction which the installer had correctly identified as creating a hazard or harm greater than the harm he or she is charged with causing.

That's for the defence not the prosecution to argue.

And besides... defer to the greater power and let the onus be on the manufacturer.

 

[bernardgreen]

And besides... defer to the greater power and let the onus be on the manufacturer.

Oh Yes, pass the buck. "" The person died but that is acceptable as the instructions were followed without question ""