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best all around zone valve? or fuggedhaboudit and use pumps? (9 Posts)
best all around zone valve? or fuggedhaboudit and use pumps?i'm a big no zone valve guy. a pump for every circuit is how i've built most systems. stubborn, sick of those old wax motor TACO's with replacement heads that cost the same as a new valve, etc. sick of rusted stuck honeywells.
of course why aren't i sick of pumps where the cartridges cost the same as a new pump. but you usually have good isolation at the pump these days and replacement isn't bad and i would tee across so i could use a good pump to run a circuit where the pump had gone, etc.
got a low ceiling job where there are some zone valves in place already but 3 new zones going on and wanted to set it up nicely and the valves would go in horizontal. i guess i could put pumps on each new circuit in old fashioned but felt like it might be worth joining the modern era.
and it feels like there ought to be enough unit demand that a zone valve ought to cost less than a pump which would be another thing in its favor.
obviously with the advent of delta p and delta t pumps maybe the argument is that you can save enough electricity when fewer zones are open that it is worth investing in one expensive pump and cheaper zones valves but this isn't a regulated fire boiler so i'd have to run some kind of primary loop, which means two pumps. of course the primary is going to be short and shouldn't take a lot to keep it circulating, on the other hand good circulation is so required in the primary that i've often seen guys just slap a standard 007 or something on anyway so where is the electric savings in that approach or is there a lower draw pump more appropriate to that kind of service?
thinking outloud, i suppose i could make the primary include the storage hotwater heater so anytime it is running its making hot water and tap the secondaries before the hot water load, but that could overheat the hotwater in heating season. guess i could add a mixing valve.
the house itself has just been spray insulated but the heat is standard issue 1970s baseboard. might be running a bit of a setback but there isn't enough element to get aggressive with setback motif.
with the new insulation and limited square footage, there is probably only so much more efficiency to milk out of the the thing so reliable operation is probably as important as efficiency gains from complicating matters, but maybe since there is going to be a hot water storage heater and the boiler can't handle condensing temperatures its a decent plan to keep that on the primary.
so , if i were to come to my senses and learn to love zone valves, what valves do you like for long reliable service at rational cost.
PS - i'm going in there. wicked witch or no wicked witch. i'm doin it for dorothy. i only want you to do one thing. talk me out of it and i'll go back to all pumps . . . which i could still do with the primary secondary approach.
PS - shows?in typical sock puppet fashion i'll be the first to reply to my own post. (and on the subject of puppets, did you know: http://www.youtube.com/watch?v=WvrDhWUE0wM )
notice i managed to miss the gas networks show which is always a chance to check out hardware, supplies and knock around these kind of ideas. i just don't think heat until october so got looking today and realized the show was a week and a half ago. any other collected trade adventures coming up in ny/ne or were they all in august?
If you're using outdoor resetdon't count on an air temperature sensing thermostat wired to an on/off zone valve to deliver the kind of room-by-room temperature management most customers expect. They work OK as a high-limit sensor for spaces with external gains.
A proportional control valve like a Belimo CCV plays far nicer with ODR -- but those don't work with most off-the-shelf controls.
Taco sentryAlthough I have had a bit of trouble with the originals, all have been replaced by now. I really like the design and the new ones fit right on the old valve bodies. I only have 2 years on the newest ones and so far so good. This is still a far cry from the 45 year old thrush motorized valves in my fathers home that seem to just keep on ticking.
Most companies over-design and then cheapen it up from there, Taco uses a different business model. After cracking open some of the older failed valves it was no wonder they failed, but that being said the new ones seem much more positive and powerful.
They use extremely low power consumption( without looking it up I think you can run 10 or 12 of these things on one 40 va tranformer) which means standby loss is minimal because most people dont turn off the power to the transformer in summer.
They use an isolated end switch which is needed for boilers like the Prestige that operate on dc current (no 3 wires allowed). Very easy to wire because of the removable molex type connectors used.
One thing to remember when buying Taco zone valves... warranty starts from date code on valve, do not buy any that have been sitting on the shelf!
sorry i got lost looking for taco sentrys and ECMs yesterdayI appreciate the posts and went to do a little research before i replied yesterday and got lost somewhere. i had heard about the initial issues with the Sentry and i'm glad to hear that they seem to have smoothed that out since the introduction.
i also find, after years of my railing about it, that they have actually added a 4 terminal head for the old - venerable might too nice an adjective - wax motor valve.
Of course no one can have a sentry in operation for long enough to really predict what their life is. I had some old honeywell elipitical ball style valves in fan coil units in one house i manage and they all went reliably at 20 years and are virtually unservicable and because of the fan coil format they are short soldered onto flared copper that is lighter than "m" i think and goes immediately into bends and they are virtually impossible to replace and impossible to service so i've been gunshy of the physical operating valves even though i was equally unimpressed with wax motors -ergo my preference for pumps
. Utlimately i just developed a method for cutting the old valves out and piping over -- kind of like getting rid of your catalytic converter in your car -- and went to aggressive reset controlled temp deliver and thermostats on a few of the fans where solar gains vs. cloud cover made so much difference that you couldn't get a comfortable temp without turning the fans on and off (and i'm still waiting for somebody to adapt the setback motif to a set forward motif for chillers but i guess that's a post for after the heating season).
It sounds like the serviceability is similar on the sentry to the wax motor style. the power use is down. i never ran a wattmeter on the wax motors to figure out what the really amounts to.
i'm glad that TACO, the HVAC favorite son roun' these parts, has a functionally competitive offering, but that gets me to my final frustration. i can't believe you can't get a decent zone valve for $50 bucks. I wonder if it is really not possible to manufacture and market them at those kind of margins or if the cost just accidentally parallels what a pump costs.
that has been the case back when they both cost 40 bucks and then 50 bucks, etc.
i've got to assume it is just coincidence here as there are a hell of a lot of units for the basic model in either category and if someone could make a cheaper one i guess they would be trying.
currently, the sentry seems to have between a 25 and 33% cost premium over the honeywell which comes the closest to the price point i'd like to see at around 60 books but i admit i'm gunshy of the honeywells from past experience. and the nameplate amps for the honeywell are actually less although i don't know if they both are designed to only draw amperage to move or whether there are hold open amps i'm not considering.
thanks again for taking the time to reply and sorry i didn't get back yesterday. if anyone is buying the sentry's cheaper than $78 bucks, let me know. that was the best i could find.
ECMpumps can be used on the primary and secondary side. So you are running two circs for the price of one, from an energy consumption standpoint. Both the motors and the hydraulics inside have been improved. I've found even some of the mod con boiler will get adequate flow with a small ECM circ.
A Delta P pumps works very well with ZV or TRVs, so in addition to less energy consumption you get better system hydraulic performance. No more over pumping.
A hydro separator or small buffer tank can also accomplish primary secondary functions.
Prices of the ECM pumps have dropped considerably. Now Grundfos, Wilo, Armstrong, Taco, and ITT have offerings.
There are big differences in the motorized, spring return type ZV when you start looking closely.
thanks hotrodso do the ECM offerings like the Grundfos Alpha have onboard delta P or what is the basis for their adaptive self-regulation?
and are there different modes for primary and secondary where on the primary side flow generally doesn't want to drop below a certain threshold. maybe that is not implicated by their normal operatiing algorithms.
maybe with the rebates mentioned in the post below, this works out. but my math says an 007 range circulator is list at .71 amps although it seems that you can get relatively similar performance from the 005 or 006 at .52 amps. with those, if they run 12 hours a day on average during heating season that is 62 wattsx12 hours = 748 watt/hours or about 3/4 of a kwh x 180 day heating season is 135 kwh x 15¢ is $20 a year, so the new pump could save you $10 a year at half the energy and maybe yield more predticable performance. cost premium seems to be about $75 to $100. so if you give my a $100 rebate i'm putting those in all day although i don't really figure whether the electric users (i.e. all of us) are actually getting a bang for that buck so i'd probably go testify against the program for giving my money away to people as i normally do whenever this crap comes up at the PUC . . .but i digress. )
i suppose as long as the rebates are in effect, i ought to replace any defunct or aging pump even on my pump based zoning with one of these if i can do it for the same money and they are determined to spend ratepayers money on this stuff.
that is another interesting thought i have. i wonder why no one makes a zone valve with flanges because the easiest way to convert these systems is to stick a single pump elsewhere and throw zonevalves in where the pumps are. of course i'd have to pay some premium for this and the valve might be best suited to being constructed with dielectric corrosion in mind so the materials might be more expensive, increasing the premium. but just a thought . . .
so assuming a decade long payback when considering upfront investment cost without the rebate, this could still be a breakeven and if you stick with an all pump system presumably they are going to run at relatively lower capacity factors and your energy savings would be even more since they would never be pumping multiple zones. and if performance is enhanced and you can afford the investment (of
course i only need to consider the cost of the unit itself as my labor
is sunk in opportunity cost into managing this fleet of buildings
anyway) why not. i assume the circuitry for self regulation is not massively expensive but i wonder if there are pumps that incorporate some of the advances but have fixed or manually adjustable flow rates that would be more economical choices for energy savings for an all pump system .
although i wonder how much of the added cost is the self regulation. while you can do things with ECM pumps that would have been far more complicated or less possible with brush style i wonder if replacing pumps in a pump only system there is a more cost effective option that just takes advantage of the loss of brush friction and hyrdraulic engineering without sophisticated flow regulation, maybe manual setting like the grundfos boss 3 speeds. or is the regulation feature add relatively little cost and you might as well just take it.
ECM energy savingsare closer to 70% (minimum) in my experience. The combination of 50% energy savings (ECM efficiency alone delivers this versus a small PSC) plus variable speed operation is a real win. When properly specified and installed, you can count on improved comfort and reduced noise. Be sure to flush & clean old systems thoroughly before installing. If there are ferrous materials in the system, a magnetic dirt separator is also a good idea.
and to add....gasnetworks is adding ECM circulators to their rebate forms. I believe it will or is already $100.00 rebate for each circ so the bite isn't nearly as deep.