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do you have ESP?

Just did a call for a customer again today. Two zone boiler, 1st floor/2nd floor. System installed in September. 1st call,10-22-02, no heat second floor. T-stat on, green light on, valve closed. Opened valve manually, worked O.K. afterwords. Replaced powerhead 11-11-02. 11-15-02, 2nd floor stat set on 67°, reading 75°, and zone valve half open/half closed. Cust. manually closed valve and worked O.K. 11-17-02, 2nd floor stat on 67°and reading 70°, valve fully open , and green light off. Cust again closed valve manually and valve worked O.K. 11-23-02 (today) 1st floor set at 70° and reading 58°. Green light on but valve in closed position. Cust manually opened and called us. Replaced 1st floor power head. Both zone valves were 02-02 date codes. New powerheads are 07-02 powerheads, and 2nd floor new head has failed twice open already in two weeks. Also we have another customer that I havn't seen but have been told that 1st call one valve stuck closed, other valve very noisy. Replaced both powerheads approx one week ago. Same customer called earlier this week and said one valve stuck open this time. I don't know any of the date codes for customer #2 but I have to assume that the new ones are newer than 02-02. What I am seeing is that Taco eliminated one problem in the heads with them not opening and now the newer heads won't always close. 1st customer wants us to rip them out and I can't blame him. The most interesting thing is going to be when and if the 4 valves we put in our company presidents house will fail and watch the stuff hit the fan when it happens.


  • Dave Palmer
    Dave Palmer Member Posts: 186

    I have to replace3 zone valves and I was going to use ESP's is there a date code to look for so I don't end up with the early ones that had problems? Job is about 40 miles from home(all back roads) and don't want any problems. Thanks Dave
  • John Felciano
    John Felciano Member Posts: 411

    The ones with the 01 date code were recalled so I doubt you will even get one.The 02 ones should be fine.Just be carefull what thermostat you use.Many of the programable ones require a resistor and some can't be used at all.

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  • Felcie

    Tell me if I'm wrong, but I think that resistor is supposed to be used so there isn't a delay to open the zone valve. You install the resistor in the thermostat, jumping RH and W which allows a little bit of voltage to trickle through and keep the capacitor in the ESP zone valve charged so that when there's a call for heat, it opens right away.

    Hey, you guys have fun this weekend. Sounds like there'll be a lot of debauchery going on with some pretty shady characters. Sorry I can't make it. There's too many men and not enough women for me.

    Best wishes,


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  • John Jr
    John Jr Member Posts: 210

    Alan your right! the resistor is to make it open faster. You just want to make sure you don't use power hungry tstat's. We have installed about 350 ESP's and have had 4 or 5 bad one's (Just the heads)

    John Jr
  • Dave Palmer
    Dave Palmer Member Posts: 186

    about good ole fashioned t87s?
  • John Felciano
    John Felciano Member Posts: 411

    Some power stealing thermostats mess up the zone valves.And can only be wired directly to the esp with a resistor.The Erie stats come to mind.They come with a resistor for this purpose.Some Honeywell's can't be used at all except when connected to a zone valve control.

    You are right the resistor that comes with the esp is for quick openning.The problem I've incountered with power steaing stats and the ESP is the valve opens as it should and than closes all by it self while the stat continues to call for heat.There is too much power leaking through.

    Call Taco for their 102-134 bulliten or I can fax it to you.

    All mechanical thermostats will work fine.

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  • jwade55
    jwade55 Member Posts: 7
    Just got a memo

    from taco themselves. Quickly put, valves prior to datecode 2/02 are affected, after this the problems seem solved.

This discussion has been closed.