bosch tankless

Mark Eatherton

If you run the haute water at the lav AND the K.S. does it get hot at the k.s.?

If yes, then look for a cross connection (tempering valve, circ returns etc...) on the h.w. line feeding the kitchen group.

Just a guess...

ME

kevin coppinger_4

I installed

a Bosch 125 tankless water heater 1 1/2 ago... all work fine except 1 faucet...the kitchen. She gets hot water at the lav (Delta 2522) the shower (moen positemp), and the washer, But at the kitchen ...1st a moen single handle faucet and now a Delta 2 handle faucet the heater seems to shutoff after a few seconds almost every time no matter how much flow is there. It is a short run...maybe 15' of 1/2" pex any thoughts???? ty,kpc

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Dave_4

The flow switch on

the Bosch needs to be tweaked.

Has the problem been there from day one? Or has it occured after enough lime built up inside the Bosch at the flow switch paddle, rendering the switch too insensitive to the slight demand of the sink faucet?

If the water is harder than 3 or 4 grains, and no softenor exists, the days of the Bosch are limited anyhow. Pull the flow switch and see what it looks like.

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kevin coppinger_4

it has been

this way from the begining....strange thing is the lav has no issues...kitchen sink w/ same of more flow problems....(probably this is the only Bosch I will install)kpc

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Ed_26

You should have a supply valve under the sink - disconnect the riser & let it flow into a pail - (shut off valve before disconnect). Possible you may need to remove the valve & riser & flush the piping as well

kevin coppinger_4

I just moved....

some of the piping a month ago...no sedimentit is 1/2 pex stop was clean, I even removed/modified the flow restricter after the problem started....The lav and the kitchen have the same areator...should be the same flow rate.....kpc

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Rich Kontny_5

How about...

The aerators on the faucet(s) did you try to remove them? These restrictors can get clogged or may not allow enough flow for the on demand to cycle.

Rich K.

kevin coppinger_4

did it...

even drilled a couple of smaller holes to allow more flow. Again the strange thing it is that thw lav never has an issue and it is the same distance away from the water heater and the same aerator.....kpc

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Rich Kontny_5

OK

Need to continue your process of elimination exercise.Go next to the tee or manifold where the line is taken off. Since it is pex put a pex valve in and try to run a line into a pail. If you have hot water there progress toward the kitchen sink.

If not there is some sort of restriction or blockage in the tee or manifold. Now work your way upstream to the heater to solve this mystery. You could also use some Sharkbite fittings because they are reusable.

These sort of problems are head scratchers but usually solvable. Keep us informed, this sounds interesting.


Rich

kevin coppinger_4

I get hot water....

sometimes...agin we are talking 10 to 15 fet from the tankless to the sink...1 3/4 x 1/2 tee then a 10-15 foot run of 1/2 pex to the sink....1/2x 3/8 stop 3/8 lav supply to the faucet....plenty of flow at the faucet...just not hot.

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Tony_23

Good call ME

I had that with a closet tempering valve affecting the shower. Boy, were those people unhappy ! When I found it and told them it wasn't going to temper anyway, they almost had me pull the Bosch. I installed an insulated tank only to have electronic problems that Bosch was VERY slow to remedy and ended up pulling it.

kevin coppinger_4

thanks...

but no chance of that...this is a really small setup/apt. only 1 bath and the kitchen sink....an inlaw apt w/ it's own hot water supply.

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Rich Kontny_5

Determine

The inlet pressure and do the math for friction loss in the line,valve and supply right up to the faucet.You may be below mininmum flow to have the Bosch cycle.

If you run the hot side of the KS faucet alone with everything else off does the heater fire up?

Is this on a municipal water system or a well?Low side of pump cycles can create problems.


Rich

kevin coppinger_4

It is on a well...

but a brand new one... all water piping is new too...40-60 psi. the tub, the lav and the washer are all fine always. It is the faucet that is very sporadic. kpc

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