boiler end switch/valve question

Just bought first house with hot water heat. Passed inspection fine, but now that winter has hit, it's been problematic: randomly stops working esp when it's cold! First service call replaced zone valve (bad end switch) Two weeks later it stopped working again. Same symptoms. I'm able to fire boiler by jumping end switch connections and then just letting the boiler cycle off it's internal thermostat. I assume the new end switch it faulty. New tech comes out and replaces the actual valve (didn't really ask, kinda did it). When I question him (more out of curiosity) he tells me the valve (small levered ball on a plate) is bad and not opening fully, thus not allowing the endswitch to connect and fire the boiler. In ANY system does the valve actually TRIGGER the end switch? It seems unlikely and a moot point as the system was working fine by jumping the end switch (which is evidence that at least the valve was open enough to pass water) Did I get snookered? P.S. do you pros out there all charge for travel time (including part pickup and getting lost?) I was charged 2.25 hrs for 50 minutes of on site work (2nd visit!) Thanks for any insight, Chris
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Jumpering safeties is not the best pratice. It is possible that the valve needs to be fully open before the end switch completes the circuit. But I sort of doubt that happens in residential systems. I have done central plant systems where a valve must be open a certain % before any pumps could run.
I have not a clue what a end switch would be. t-stat?
Sounds to me like you need a pro to come out and teach you the operation of the system.
Unfortunately charging of the customer is left up to the company called. Sounds like the guy you called gets paid per call. I work on a minimum of 4 hours for my work with in 50 miles and 8 hours over that plus travel expenses over 50 miles.
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Both Honeywell and Jayco require 100% opening of the valve before the end switch is made, If you push the stem all the way over it opens the valve but NOT the end switch, the motor has to take the drive past the 100% open point to make the end switch.
This guy is lucky his limit worked and hopefully the releif of he would be dead instead of posting these questions,
As to the call, pay it and be glad the guy saved your life, you were in severe danger of an explosion for what you did. If the pumps outlet is before the valve that alone could create high enough temperatures to cause major problems.
Don't work on things that can kill you!

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geoman wrote:

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Well in my defense, it was the technician that recommended (and talked me through it over the phone)that I jumper the end switch connections to fire the boiler. So I suppose he and his company are lucky as well,...He assured me it was perfectly safe (yes I asked): "It's only 24 volts; no danger!" It is in fact a Honeywell, so it's good to know that the valve must be 100% open. It's a little frustrating that a company can charge a customer twice for fixing the same problem ONCE. I was informed that the original tech would be out, but instead had to start over with a new one. Believe me, I will from now on take the "expert" (purchased none the less) advice with a grain of salt.
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Typically the end switch of a zone valve closes a circuit on a relay which turns on the circulator pump feeding the zone valve, which in turn may or may not turn on the boiler, depending on how the boiler is wired to fire. The zone valve must open past 100 % to activate the end switch. It sounds like either there is an obstruction preventing the valve from opening completely or the end switch is bad. There is no danger in jumping the switch as long as the valve is open enough to pass water, if not eventually you'll burn out the pump

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RBM (remove this) wrote:

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Thanks for the detailed explanation. I appreciate your time (and all others). Makes perfect sense and I understand why the tech replaced the valve rather than just try to clear it,...It's just a drag that the second tech had to come out. My big issue was that the first visit did not include any off-site (travel, etc) labor charges, and at $90/hr I expected them to catch it the first time (or at least cut me a break on the 2nd call)
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That's your first problem, trusting your 'inspector.' Most are inspecting from a general list given to them at the class they took. Another possible problem was that they ran the boiler for just long enough to see if it worked. Now that it's cold, longer run times are the norm.
First service call replaced zone valve

The prices charged are between you and the contractor.
As far as the rest, the other responders have it pretty close to correct.
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