Honeywell RLV430 install help!

I have purchased 5 of these programmable thermostats for my home to replace the older chromalox dial types. the heating is 240v in ceiling radiant and the original stats are 4 wire where the new honeywells are 2. I have followed the instructions for installing to a 4 wire system and am getting power to the stat and heaters.. the problem is the heater will not cut out. if i turn it down all the way to 5 deg the lead going to the heater is still showing the same voltage and the heater stays on.. I even tried swapping out a diff unit and the same thing.. I wired it as instructed.. one of the 120 v leads get tied off to the lead in to the heater stays "hot or live" then the other 120v to a lead on the new stat and the other to the other lead on the heater. This is supposed to work with the stat cutting out the full voltage when needed. but the unit keeps the 120 constant( tested with multimeter)
Any thoughts or suggestions would be appreciated
Bruce
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Have you checked the test stat off line? Your description sounds like the contacts are welded shut. Line voltage thermostats are usually simple things so cycling through the range with your meter attached should show definite off-on readings. If the mystery continues, call Honeywell customer service for advice.
Joe
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wrote:

Have you checked the test stat off line? Your description sounds like the contacts are welded shut. Line voltage thermostats are usually simple things so cycling through the range with your meter attached should show definite off-on readings. If the mystery continues, call Honeywell customer service for advice.
Joe
Is it possible that you are reversing the line and load wires that are connected to the stat?
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there are no indicators as to line and load on the new stat.. Just 2 black wires.. I tested continuity and one is closed and the other open, however i get the same results.. always on when hooked up.
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Can you be more specific about your test? With only 2 wires you have continuity between the pair, right? That says the contacts are closed. Now if you change the stat setting the contacts will show open, correct? That shows the contacts open properly. The stat is in series with one input line to the heater, if like most conventional units. it is operating as a single pole, single throw switch and there is always voltage (to ground if you're testing) at the heater terminals. HTH
Joe
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dumb it down for me? I'm not an electrician... have some knowledge and can read diagrams..line and load throws me off
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What I described was a simple test for stat function. Without circuit diagrams/instructions for old and new systems further speculation won't be very useful. Mzaaybe someone in the NG has dealt with an identical system successfully, which would be the info you need. Good luck.
Joe
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