MYSON TRV stuck in high temperature mode

[nairb999]

Water level in F/E tank does not appear to move. Similar level when heating is ON or OFF so should n't have a problem with fresh water entering system.

Will monitor more closely - certainly no pumping over problems

 

[Softus]

Water level in F/E tank does not appear to move.

Some expansion will take place up the vent pipe, but if the level in the F&E really doesn't move at all then you might have a blockage in the cold feed. In this scenario you could easily be drawing air down the vent.

You'd find out by draining the system, so don't do it unless you have a few hours to spare.

 

[nairb999]

Water level in F/E tank does not appear to move.

Some expansion will take place up the vent pipe, but if the level in the F&E really doesn't move at all then you might have a blockage in the cold feed. In this scenario you could easily be drawing air down the vent.

You'd find out by draining the system, so don't do it unless you have a few hours to spare.

I presume expansion will take place through both vent pipe and cold feed pipe. Expansion up the vent pipe will not result in any change to F/E level but expansion in cold feed pipe will increase level. How much increase should I expect between hot and cold ?

 

[Softus]

I presume expansion will take place through both vent pipe and cold feed pipe.

Correctamundo.

Expansion up the vent pipe will not result in any change to F/E level

Er, that's a non-sequitur, unless the cold feed is blocked, in the event of which you would be correct.

...but expansion in cold feed pipe will increase level.

Yes.

How much increase should I expect between hot and cold ?

3% of the volume of your system.

 

[nairb999]

Er, that's a non-sequitur, unless the cold feed is blocked, in the event of which you would be correct.

Do excuse my ignorance and not wishing to be a pain but are you saying that during normal heating water should enter the F/E tank from the vent pipe?

As I said very early on in our discussion during the boiler on cycle the cold feed pipe gets very. Does that not indicate there is not a blockage?

 

[Softus]

Do excuse my ignorance and not wishing to be a pain but are you saying that during normal heating water should enter the F/E tank from the vent pipe?

No, but you can't have a rise in the vent without an identical rise in the F&E, unless the cold feed is blocked.

As I said very early on in our discussion during the boiler on cycle the cold feed pipe gets very. Does that not indicate there is not a blockage?

Depends on where you put your hand. If near the circulating water then the cold feed pipe will get hot both by conduction and, if not blocked, by convection.

 

[nairb999]

Depends on where you put your hand. If near the circulating water then the cold feed pipe will get hot both by conduction and, if not blocked, by convection.

It is too hot to touch 2 feet above "t" connection.

If there is a blockage would it be possible to connect a mains feed to vent pipe and reverse flush

 

[Softus]

It is too hot to touch 2 feet above "t" connection.

That's a reasonably good sign.

If there is a blockage would it be possible to connect a mains feed to vent pipe and reverse flush

Not really - this rarely achieves anything except for stressing lots of components and causing leaks.

However, if you were to construct a means of gently pouring water into the vent, and you saw the water level in the F&E rise up, then you'd know that there was no blockage. There would be nothing wrong in cutting the vent (above the water line) to facilitate this, and joining the pipe using, for example, a push-fit connector (for ease of doing it).

Or you could drain a gallon of water from the system and check that the F&E ball valve opens and lets water in.

 

[nairb999]

However, if you were to construct a means of gently pouring water into the vent, and you saw the water level in the F&E rise up, then you'd know that there was no blockage. There would be nothing wrong in cutting the vent (above the water line) to facilitate this, and joining the pipe using, for example, a push-fit connector (for ease of doing it).

Good call - I could easily rig up

Or you could drain a gallon of water from the system and check that the F&E ball valve opens and lets water in

This has already been checked when added X400

I think I am sorted now - once again many thanks for all you time

 

[D_Hailsham]

A small hammer is a perfectly acceptable, and commonplace, way of both testing and movement of and freeing off a TRV pin.

And how, exactly, do you use a hammer to free a pin which is stuck down?

Hitting the pin, even gently, will cause damage to the working end of the pin. The pin has to be pulled free; and a pair of pliers, used carefully, will do the job without damaging the pin.

 

[Softus]

And how, exactly, do you use a hammer to free a pin which is stuck down?

By hitting it, and not being a pratt.

Hitting the pin, even gently, will cause damage to the working end of the pin.

No it doesn't. I do it all the time, as do thousands of plumbers up and down the country. If you're particularly ham-fisted, which I infer that you are, then just use a soft-faced hammer.

The pin has to be pulled free;

No it doesn't. For one thing, the pin is rarely stuck - it's invariably the valve that sticks on its seat.

and a pair of pliers, used carefully, will do the job without damaging the pin.

You are indescribably foolish and hard of thinking.

 

[D_Hailsham]

And how, exactly, do you use a hammer to free a pin which is stuck down?

By hitting it, and not being a pratt.

I must try that technique the next time I want to take a nail out

Hitting the pin, even gently, will cause damage to the working end of the pin.

No it doesn't. I do it all the time, as do thousands of plumbers up and down the country.

Maybe that's why so many plumbers are treated as "cowboys"

The pin has to be pulled free;

No it doesn't. For one thing, the pin is rarely stuck - it's invariably the valve that sticks on its seat.

That implies that the pin is separate from the valve, are you absolutely certain?

and a pair of pliers, used carefully, will do the job without damaging the pin.

You are indescribably foolish and hard of thinking.

I said pliers, not stilsons. If you don't know what I mean, here is a picture:

I'll treat your last comment with the contempt it deserves and add you to my ignore list.

 

[Softus]

And how, exactly, do you use a hammer to free a pin which is stuck down?

By hitting it, and not being a pratt.

I must try that technique the next time I want to take a nail out

Your sarcasm is wasted here.

Hitting the pin, even gently, will cause damage to the working end of the pin.

No it doesn't. I do it all the time, as do thousands of plumbers up and down the country.

Maybe that's why so many plumbers are treated as "cowboys"

You could be right, but I really don't think so.

The pin has to be pulled free;

No it doesn't. For one thing, the pin is rarely stuck - it's invariably the valve that sticks on its seat.

That implies that the pin is separate from the valve, are you absolutely certain?

On some valves it certainly is, but I can believe that on other valves it isn't. Your failure to recognise both possibilities is what makes your bland and bad advice particularly wrong.

and a pair of pliers, used carefully, will do the job without damaging the pin.

You are indescribably foolish and hard of thinking.

I said pliers, not stilsons. If you don't know what I mean, here is a picture:

S'funny - even though I know the difference, the picture is still visible. Notwithstanding that, I'd just love to watch you attempt to grip a TRV pin with a pair of Stilsons.

I'll treat your last comment with the contempt it deserves and add you to my ignore list.

You can run, but you can't hide. Ignoring me will make it much easier for me to alert those people to whom you give wrong and bad advice, so I thank you for that.