Piping advice

Robert O'Connor_12

Thank you for your reply!

Robert O'Connor_12

Piping advice (Robert O'Connor)

I have a customer who wants a "third" opinion. I told him I'd post a question here and he agreed to abide by the advice given. I'm going to try not to disclose "my" opinion for the sake of fairness.

Here goes!

Advice on installation. Customer has mod-con boiler running 5 radiant zones and an indirect(see: http://forums.invision.net/Thread.cfm?CFApp=2&&Message_ID=425775&_#Message425775 ). Customer wants additional zone to serve finished basement. Current set up is single pump w/o mixing valve,Low Loss header, using outside temp. sensor. Every room in this house has a t-stat controlling radiant manifold valve actuators. Customer does NOT want another radiant floor, walls or ceiling, nor are they crazy about panel rads. Customer wants to use "trim like" radiant panel baseboard. The vendor proposing the emitters requires the addition of a mixing valve. The original system is a very low temp application (max temp @ 125 degrees). The only way to apply these radiant baseboards in order for them to provide necessary btu output would be to increase water temp to max setting of boiler and install mixing valve to the rest of house.



My question? Would installation of mixing valve defeat purpose of mod-con boiler since it would need to provide water temp well above the rest of systems low water temp. requirements thus not allowing it to condense.

Open to suggestions


Robert O'Connor/NJ

Mark Custis

I don't think

in the overall design the load on the system at high temperature will cause a non-condensing event to occur very often.

zeke

If the baseboard installation is sized large enough for say 150 deg, then together with the setback feature and the fact that most times you wouldn't be at the max, then the efficiency hit should not be significant.
Moreover, I don't see this as an issue if the boiler is already there. I would honor the customer request unless he is ambivalent about radiation vs baseboard heating in the new zone.

Robert O'Connor_12

zeke

Thanks zeke.

Dave Yates (GrandPAH)_11

read an interesting

full-page ad by Warmboard on the back cover of either Solar Today or Home Power mag that detailed the increased cost for heating when you elevate water temps. First time I've seen that in writing & it was well presented. You might want to give them a call.

As for raising the temp, why not just add more emitter? Runtal has excellent charts to give you BTUs per foot at various temps. I've used the charts to size for existing low-temp systems to avoid excess costs for multi-temp zoning or controls.

Robert O'Connor_12

Hi Dave

I don't get either mag. Anyway to post article?

The customer doesn't like the look of the Runtal, says it looks "too commercial". Increasing the size of the emitters IMHO is the only way but would make them almost 14" high and they didn't go for that either.

As you can see by the pic's, I don't have much room to install a mixing valve and tees for the new zone location without butching up the install.

Thanks for the comment!


Robert O'Connor/NJ

Andrew Hagen_4

Radiant Baseboard

From what I understand of mod/cons, the modulation is at least as important as the temperature. So at high temperatures and low heat load (low temp rise), the boiler is still relatively efficient, maybe in the low 90's. If it is cycling, that may not be true, but if the boiler is running continuously at low modulation the efficiency is not terrible.

I would prefer a lower temperature emitter, but as long as the baseboard will cover the load, the efficiency hit might not be too bad.

Edit: Viessmann publishes this chart on their Vitodens brochures.

Dave Yates (GrandPAH)_11

it's at home

in the 'reading room' - the only place in the world where I can get some peace & quiet! I have three or four mags I'm reading & two books in there(G).

I e-mailed Warmboard to ask if they have a link to the ad copy.

Robert O'Connor_12

Dave

Thanks Dave!

reading room eh.....


Robert O'Connor/NJ

Robert O'Connor_12

Andrew

Thanks for your input.


Robert O'Connor/NJ