Lochinvar Noble flow control valve?

Novaman854

Hey everyone. I'm installing a Lochinvar Noble 110 combo and have a question I'm hoping you can help clarify. On the domestic hot water, they are showing a flow control valve on the hot water supply out of the boiler. I can't seem to find a flow control valve that is suitable for potable water. How is this typically handled? Thanks in advance for any help.

DZoro

Personally I have not seen a great reason for one, so have not put them in.

Novaman854

Ok. Thank you.

hot_rod

the shower valve is the flow control If the output cannot keep up, just flow down the shower valve.

Novaman854

Ok, so consensus is that it's not needed. Thank you. Obviously I'm not a professional, but I'm trying to do my best by following the manual exactly. I didnt really see the need for an expansion tank before a tank less either??

SuperTech

> @Novaman854 said:
> Ok, so consensus is that it's not needed. Thank you. Obviously I'm not a professional, but I'm trying to do my best by following the manual exactly. I didnt really see the need for an expansion tank before a tank less either??

Some models have an expansion tank for hydronic heating built in. Code and common sense dictates that the domestic hot water needs one on the cold water inlet.

Alan (California Radiant) Forbes

The question is: Considering that it is an on-demand heater, is there enough expansion to require an expansion tank?

A hot water tap is opened, burner turns on and heats the water. The water expands, but the tap is still open, relieving any thermal expansion.

hot_rod

I run my Nobel combi in the hot always mode, so it might be good to have one of those baseball sized exp tanks if you run that mode. No harm in having one.

wesPA

@hot_rod, i was curious about the always hot mode, have you always run yours like that? I have had my Noble in for 2 seasons in heat only. Getting the domestic piping tied in has been on my list, but it remains there🙂. I was planning on adding the expansion tank and the mixing valve, I also had wondered about the purpose of the flo control.

Novaman854

Yeah that's what I was thinking. In order for the boiler to turn on, a valve would have to be opened - which wouldn't allow pressure in the first place. But I will intall it as the manual says. That's why I was going to put in a flow control valve (because Lochinvar recommends it). But I am unable to find one designed for use with potable water? I also asked Lochinvar this question through e-mail, but they did not respond.

Alan (California Radiant) Forbes

Rinnai includes one with their boilers.

Novaman854

This is the only flow control valve I can find that can be used for potable water. The problem is, it's only 1/2 which I don't think would be suitable.

BillyO

just install a ball valve and throttle as/if needed. Keep it simple, stop overthinking everything

Novaman854

Ok. Got it. Thanks

hot_rod

wesPA said:

@hot_rod, i was curious about the always hot mode, have you always run yours like that? I have had my Noble in for 2 seasons in heat only. Getting the domestic piping tied in has been on my list, but it remains there🙂. I was planning on adding the expansion tank and the mixing valve, I also had wondered about the purpose of the flo control.

When I first installed mine I used the cold start option. But the combination of my long piping runs and the ramp up time, I was running a lot of water down the drain. So the always hot did lessen the water waste. I'm not sure it uses that much more LP, as the boiler is warm most of the heating season anyways. In summer I have enough solar thermal to turn the boiler off completely.

I really don't see the need for that flow control valve which may tend to scale up and restrict too much. If the unit cannot keep up, just throttle back the flow on the faucet.
Really the only time it would be an issue is in the shower. If the DHW temperature drops a bit at the washer or dishwasher it's not a big deal for me.

Also with solar pre-heat, if I use the flow control it limits too much when I run the hose or other high flows, and I have high incoming temperature.

BoilerToolbox

The flow control valve isn't required. It is there to throttle the flow and increase the amount of time that the water spends in the heat exchanger, allowing it to get up to temperature. If the flow is too fast, it won't get as hot as you want it to be at the fixtures. You can either use a ball valve as has already been suggested, or Watts offers a LFCSM-61-S, which is a circuit setter rated for potable use.

For your expansion tank question, it is needed if you are doing any kind of re-circ. The system will be "closed" when the call for heat is generated by the re-circ pump and will therefore need an expansion tank.

Novaman854

I do like the idea of a simple ball valve. As far as the expansion tank, I will install it as specified. But it is not a re-circ system.

hot_rod

What is your incoming water temperature

Novaman854

I'm honestly not sure. Hoping to get the well up and running shortly. I would assume 50-55 degrees. The home is in southern Maine.