PM on my radiant system and questions....

Boring

Have a Knight condensing boiler and in floor radiant heat...system is about 16 years in service with only minor repair problems---most expensive was a control board replacement...ouch! Was doing my annual boiler cleaning a few weeks ago and it was textbook...clean flame sensor and igniter, condensate line, burner, flush the exchanger to remove all the crud.... I've never flushed the whole system...is that something that should be done? Also, never fussed with any of the Uponor zone valves...I have one that squeals when it activates randomly...I popped the "motor" off and reinstalled it...it looked like it may have never been installed all the way??? I was surprised that the circulator pump changed tone when the motor was taken off and then reinstalled...are these valves normally open or closed? I never ever really looked at them, but it appears they are on the return side.... I have 13 valves on the system and 7 T-states...when a stat calls for heat...I presume the motor opens the valve so flow can start...the top of the valve motor exposes a green ring... I also have a PRV that opens to keep the circulator from dead heading...How does one know if that valve is adjusted properly? I was reading that all the valves should be opened...then the PRV valve is opened just enough to allow flow then backed off about 1 turn....does that sound correct? Any suggestions would be appreciated.....Thank you

Boring

EternalNoob

Lotta questions, I'll take a stab at the easier ones to give the old timers a break.

PRV's:
I don't know what type you have so not sure about adjusting it. The watts type typically installed on radiant systems have a narrow range of 14-17 psi, and there isn't any need to adjust that. If you do for some reason, try a you-tube search on your particular valve, it'll be easier to follow than a texted explanation from the forum. The watts PRV i have has a seemingly unnecessarily complex procedure which involves un-threading the top piece, removing a pin... Others, like the caleffi, are just a matter of turning the valve knob. If you don't have a pressure guage just after the PRV, install one, they are good to have.

Having said that, after servicing your system and letting it run a few days to bleed out the air introduced during servicing, the best practice recommendation is to then shut off the ball-valve next to the PRV for the long term, keeping the system isolated. The main reason being that in a closed loop radiant system, if you are loosing significant pressure over time, that means you have a leak somewhere and you'd rather know about it than have the PRV masking the problem by continually topping off the system, while your walls/ceiling/basement fills with water. If you had an unlikely catastrophic leak while not home, the worst case scenario then is that the volume of your closed loop system (a few gallons perhaps) leaks into your house rather than hundreds of gallons.

Not familiar with the uponor valves, but yes most zone valves are the normally closed type. Normally open valves are used for other actuator applications.

Flushing out the whole system is not advisable to do every year. No big deal, but you'd just be introducing fresh oxygenated water that will shorten component lifespans. Every few years maybe a good idea, but i've heard conflicting advise on that so i'll let the pros elaborate. I flushed my radiant water out after not having done so for about 7 years and was surprised at how clear and odorless it was, and I was like, well i guess that was unnecessary.

Otherwise, you're probably safe at betting on if it ain't broke don't fix it.

Boring

Oops, I meant Pressure differential valve to ease dead heading the circ pump...not a PRV....
Thanks for your feedback...agreed on the "if it ain't broke, don't fix it....

Zman

Those zone valve powerheads have thermal wax in them. They actually heat up and open, thats why they take so long to open. Most if not all are normally closed.
For the pressure differential valve, I usually set them to the for the pressure I would like to see to the circuits. Oftentimes, the circulator is not designed to achieve optimal flow on the rare occasions that all the zones are calling it does achieve those flows most of the time (some zones satisfied). The technique you describe is one I have heard of. It probably works pretty well as a starting point.

hot_rod

which Wirsbo Zone actuator? they used the Honeywell/ Sparco version for some years. A motorized rack and pinion type, they did make some noise.

Boring

<<img src="https://us.v-cdn.net/5021738/uploads/editor/o1/204y48dmvavc.jpg" alt="" />


Uponor 4 wire zone valves....appears these valves are no longer available, but there is a alternate with a blue housing...
Honeywell differential valve....

Hopefully the attached will open....
Also, I've always kept my supply water valve open is that normal or is it best to close them? I did have the original PRV fail and that caused a pressure rise in the system...then I closed the valve until it was changed...the bladder tank was also bad at the same time....

hot_rod

Helmet heads, Uponor has used so many different types and brands over the years, only they know which cross over.

When the actuator is removed the valve pin will spring up/ open. To close that loop put the blank plastic cap on and screw it down or screw on the actuator. As the actuator heats it allows the pin to pop up with spring tension

When an actuator fails, removing it will open that loop to flow 

The bypass valve, with all zones open and flowing put a hand on both sides of the valve, there should be no heat felt on the outlet, screw it down until that is the condition.

As soon as one zone closes off you should feel some temperature on the outlet

In the future upgrade to a delta P circ and lose that parasitic device👌

Boring

So those Uponor "helmets"/zone activators have wax or something in them and are not mechanical...ie gear driven?

How does one go about sizing a Delta P circulator pump? Replaced my Grundfos UPS26-99F PN:99218679P1 several years ago and remember looking at variable speed pumps and someone suggested this would be a difficult one to to replace going that route....?

hot_rod

Yes, thermal actuators is what they are called. A wax copper mixture inside, like this.

There is a delta P circulator available for most every application now. Every pump manufacturer offers a wide selection.

Calculate what you need for the system and cross it over to the ∆P model. Type of fluid, gpm and head is what you need to know.

Idronic 16 may help you.

https://www.caleffi.com/sites/default/files/coll_attach_file/idronics_16_na_0.pdf

Boring

WOW, thanks for the info...tons of good information in the attached idronics 16...
I haven't looked at the installers notebook in a long time...I'll have to revisit that and review the notes to see what's all there....In my opinion, they did a great job as the system has done all we wanted it to do...
The only thing I never liked is the uni-strut channel that supports the whole system is fastened to wood studs for the house structure which amplifies everything....transformer hum, circulator hum....was always going to redo that and anchor it to the concrete floor, but haven't gotten around to that yet....

The installer taught me all kinds of stuff and was always willing to coach me through repairs and answer questions and cut me deals on parts.....He passed away a couple years ago...my he rest in peace...I'll never forget him....

Boring

circulator pump sizing looking to update to a varaible speed circ....current pump is a grundfos UPS 26-99FC 1/6hp

The computer has not been my friend in searching for circulating pumps....

Zone 1 is the basement 1/2" pex in gypcrete approx 675ft- 6 loops flow 3.1usgpm; head loss 8.8ft; control - 1 zone valve
Zone 2 main floor 3/8" pex w extruded plates..14 loops... flow 3.8usgpm; head loss 4.9ft; control 9 zone valves.

The only thing I could find was a groudfos magna3 32-120F...with no specifics...

hot_rod

what about the Alpha 26 99

Boring

By golly, I'll bet that pump would work perfectly....then I could just shut that bypass valve down, or close the ball valve on that bypass section, Correct?

hot_rod

Properly set up in salta P mode, that pump should eliminate the need for the bypass valve, valve it off

Boring

Thank you Hot Rod....I really appreciate your suggestions and guidance!!!

Paul Pollets

With your load, you would only need the Alpha, which can do 15gpm at 15' head. I did notice the piping of the PDV is on the pump outlet. Normally the device is piped between the pump's inlet and outlet. Valves and unions are used to isolate or replace the device easily. The supply is 3/4" and don't see any mixing device. Are you sending the same temps to each zone? There's also a 1/2" reduction at the PDV connection. That could increase head requirements for the pump.

Boring

No 1/2" reductions..does reduce to 3/4" to go through the PRV and ball valve...One temp for the whole system...The whole basement is on one thermal activator....many loops 3.1 gpm...the upstairs main area is 3.8 gpm with 10 thermal activators...one stat for the basement.... 6 stats upstairs...I would imagine the bypass sees more action from the up stairs... original install in 2007 with Indirect water heater...replaced the pictured circ pump in 2017.....I suppose I may have to start looking for my next boiler???? Don't really know the life expectancy on them...20 years? knight KBN 080....love it! Was "PDV" a typo? or what does the stand for?

Boring

Oh man...these senior moments are coming more frequently>.... PDV===Pressure differential valve....PRV====Pressure reducing valve---------My Bad----Cheers

Paul Pollets

PDV is a typo. PBD is the correct nomenclature

hot_rod

PAB is another "pressure activated bypass"

Boring

Acronyms...make my head spin...I suppose they are all familiar if ya work with them on a daily basis...

Thanks again....

Boring

Finally got around to installing the alpha 2 26-99 ECM....wow! Smooth, quiet, efficient....P-autoadapt mode. No more pressure differential bypass and half closed ball valve....Life is great!

Boring

Been noticing now that the outside temp is warming and a less requirement for heat the Alpha 2 26-99 ECM seems to make a variable sounding hum...is this a sign that the P-autoadapt mode is relearning for lower flow based on fewer zones opened and lighter heat requirements?