Potterton PTT1 and PTT2 wiring problem

[ian4c]

I wonder if anybody can help with this wiring problem.

Just changed over from the PTT1 for no reason other than the PTT1 is 20 years old.

Wiring is the same except the PTT2 calls for a an extra live from the programmer.

I wired as per the instructions but without a live to 4 TL. Started HW and no start. Press Boost and boiler starts diverter valve operates and closed on reaching temperature.

Since PTT2 (4) TL requires a live from the programmer I put in a link between 2 and 4. This caused the relay to dance!

Any help will be much appreciated.

Great site!

Ian

Untitled

• ian4c
• 4 Nov 2008
• 2

Untitled

• ian4c
• 4 Nov 2008
• 3

 

[Spark123]

2 doesn't appear to be live - it connects to the Cooling?? 3 appears to be the permanent live, if you link this to 4 does this work?

 

[ian4c]

2 doesn't appear to be live - it connects to the Cooling?? 3 appears to be the permanent live, if you link this to 4 does this work?

Thanks Spark123.
Correct! My mistake " I put in a link between 2 and 4" I meant to say between 3 the live and 4 (TL)

Yes, I linked 3 to 4 which seemed the obvious but on power up the relay rattles away.

At the moment the only way to to start the HW is by pressing the Boost button. Strange. Any ideas?

Another strange thing. After pressing Boost and then later the HW is satisfied. If the stat then calls for HW the only way is to press Boost again!

The instructions say ' Terminal 4 (TL) should be connected to the 'Hot Water on' output of the timer' (Term 3 on the Potterton programmer) it goes on to say Terminal 3(L) is for permanent live supply and must be connected to the time control L on a Potterton programmer. So I assume both 3L and 4TL are live?

Ian

 

[Spark123]

With the clock removed can you test each terminal with a volt meter to see which terminal is permanently live? (5 should be neutral - use this for the black lead on your meter)

 

[ian4c]

With the clock removed can you test each terminal with a volt meter to see which terminal is permanently live? (5 should be neutral - use this for the black lead on your meter)

Spark123. Thanks again.

Programmer off. Front off- No live. Programmer on either with HW or heating No live!

With power off to replace front I notice LED calling for HW is on. Turn up and it's off.

Power back on the the programmer HW - no start but Heating on - boiler starts.

Ian

 

[ian4c]

With the clock removed can you test each terminal with a volt meter to see which terminal is permanently live? (5 should be neutral - use this for the black lead on your meter)

Spark12. Hello again. Please disregard the last message in answer to your question. I was working on some low voltage stuff and believe it or not I had the meter set incorrectly. I know! - I can hardly believe it my self.

With power on to the Programmer.

All off 2(C) is L
When the boiler is calling for HW 3 (L) is Live.
When the boiler is calling for CH 2(C) is live but not 3 (L).
When the CH is turned off 2(C) is Live

When both CH and HW on 3 (C) is Live

Ian

 

[Spark123]

What does the TL terminal do?

 

[ian4c]

What does the TL terminal do?

Hello Spark123

(4) TL according to the wiring diagram should be live when the timer programmer switches on. It also says that 4TL should be connected to the 'hot water on' output from the time control (term 3 on a Potterton programmer.
Terminal 1 Heating should be connected to the boiler or 'open' wire of the hot water zone contol depending on the type of system. terminal 2 (Cooling) if required should be connected to the 'Close' wire of the hot water zone control. Terminal 3(L) is a permanent live supply and must be connected to the time control on a Potterton programer.

What I don't understand is the instructions call for a live to 4(TL) from live on a Potterton programmer. Terminal (3(L) also has to be live from the same source? is this correct. I did put a link between 3(L) and 4(TL) but this caused the relay to bounce and rattle.

I wonder if a link from 2 (live when central heating is off) is put to 4(TL) to start the boiler in HW mode?

Ian

 

[gas4you]

Don't know this one, but from your last post it sounds feasible, could be that this is working the same as a 'Y'plan, but using the ch off for power instead of the HW off on a 'Y' plan

 

[ian4c]

What does the TL terminal do?

Spark 123

Have you given up on me?

Gas4you says "but from your last post it sounds feasible"

Not tried it yet - What do you think?

I tried to speak with Potterton Support. Spent 30 minutes waiting on hold with a message every 20 secs or so, to say somebody would answer. So I telephoned Sales. Answered right away!! Well they would for sales. So I explained I had been on hold (premium?!) to Support and he tried to get hold of them. After 10 minutes he said Support would telephone back as soon as they were free. It has not happened! now several days!

A few years ago I used to speak with Potterton ( the old company) The service was great. Not any more. Will I buy another Potterton /Baxi product again? I doubt it!

Ian
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[Spark123]

Just re-reading what is going on - there is no terminal in there which is live all the time which sounds like it could be your problem.
You say the ppt2 requires an extra live from the programmer? Is this a permanent live?
Are there any wiring examples in the booklet?