1992 Stadler Install needs an outdoor reset upgrade

semma

First, thank you in advance for your time and help. I will surely pay it forward whenever possible.
I just moved into a home that was built in 1992. I bought it from my best college buddy. He installed a veissmann boiler with radiant heat through the house. The system has four zone controllers. Three are taco controllers and one is a viega for the basement floor radiant. On the main panel, there is a stadler wd-23 outdoor reset control, but the outdoor sensor is gone. I think they remodeled outside and the sensor is a casualty. Also, there's a supply temp sensor that is hanging off and not connected to the pipe. The mixing valve actuator is also not installed and hanging off the wd-23. The diverter appears to have been retrofitted with a stadler non-electric actuator which is connected to a capillary senso on the supply side manifold. The manifolds are stadler and the diverter appears to be stadler. There are a number of wires running from the wd-23 which look to be labelled rm sensor, outdoor sensor(missing), boiler, boiler sensor, etc. I've contacted viega and they suggest I replace the Wd23 with a viega basic heating control, a new mixing valve actuator, an outdoor sensor, and a new room sensor. Here's where I need help... I'm handy, but a novice at this system. My friend owned an oil company and they did all the service. I don't have unlimited access to technicians like he did. They tech who maintained the system seemed to recall that the stadler manifolds and divert r valve are metric and therefore would be incompatible with the newer viega valve actuator. Does anyone have any recommendations? Would it be better to consider Teckmar or wirsbo for reliability, comparability and ease of install or am I best off with viega? Oh... I also found a very small brass pin with a ball on the end which looks like it belongs to the valve actuator... Not sure if that's significant info. Thanks again! It's a puzzle.

semma

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hot_rod

What type of boiler is this connected to? If it is oil fired, you will want a control that also have a boiler return protection function.

semma

It's an oil fired veissmann boiler. Thank you. I will make sure that there is such a control.

semma

To be clear... This is a control that makes sure the return temperature is not too low as to create condensation ? The veissmann has some controls on top here's a picture.

Robert O'Brien

An oi fired Biferral or Vitola can handle low return temps

Ironman

Is the basement radiant all one zone? If so, then the actuators are unnecessary. If not, Rehua's may fit. You could buy just one and try it. But I've never seen one of the wax cartridge type fail; I've replaced many of the micro motor type.
The attached pic shows some I did last week.

Ironman

Here's the pic

semma

Thanks Robert and Bob. The basement has four zones thus the many actuators. I know that they've replaced many of the old stadlers with viega /stadler then viega. I will look into this wax type you mentioned in case any go bad. I guess my main concern is getting a diverter valve actuator that it fits the diverter valve. The numbers on the diverter valve are dn25 pn16. Are the diverter valves one standard size or are they matched to the actuators from the specific brand? Will any valve actuator fit it or must I get a stadler viega which matches the diverter ? Are they threaded differently? I've heard that the older stadler mixing units/ diverters are metric ?

JeffM

Stadler diverting valves do have metric thread, but the current Viega ones are the same. A new diverting valve actuator from Viega will fit.

semma

Thanks Jeff M! I am wondering why they disconnected the actuator and supply temp sensor from the wd23 and installed a non electric diverter actuator. Perhaps there's something wrong with it the wd23 outdoor reset and needed a quick fix. I'm inclined to go with the basic heating control from viega, viega diverting actuator, viega outdoor sensor, indoor sensor, and supply sensor. There's also a wire for boiler sensor... I will need to figure out how that plays with the basic heating control.

Paul Pollets

You could retrofit the boiler with a new Vitotronic 200 control. Viessmann does sell a housing for conversion. You would also need a 4 way mixing valve and motor to mix the temps. Only the Viessmann valve would be compatible with the V200 control. We've had to retrofit many of our early installations as the original computer or control glitches after 10+ years.

semma

All, I have decided to purchase a Viega Basic Heating Control 16015 with outdoor sensor, supply temp sensor three way diverter valve actuator, and indoor sensor. It looks like a fairly easy retrofit. The only remaining question is: will the diverter valve actuator fit my 24 year old stadler three way diverter valve. The tech at viega seemed to think so. I guess I won't know until it arrives. I've been reading up on the basics of radiant heat and outdoor reset. I'm hoping this system pays for itself in fuel savings. The Basic Heating Control is made by Tekmar and private labeled for Viega.

semma

Well here it is! I finally installed the viega basic heating control with outdoor and indoor sensors. It's quite a system. Just one last question. I know each house and each service area will be different and a tuning in period may be necessary. Based on my house, what do you think the design temps should be set at? I live in zip code 01430, Ashburnham, Ma. It's probably the coldest part of Massachusetts. On top of that, we are on the south side of a lake with several large two story window walls facing the north wind. The house is tight, 6 inch construction, well insulated, and modern doors and windows. It's about 4200 sft built in 1992. The pex s in conduit, in concrete in the basement, gypcrete on first floor, and wall units on second floor. I have four separate stadler manifolds and 14 thermostats with two zones open to the main heat loss area. The indoor sensor is in that area. I have a Veissmann oil fired boiler circa 1992 with a riello burner. My basic heat control is set to "burner enable" but the viessman looks like it controls itself and has a control on the top. Looking to get your suggested start up settings for outdoor design temp, mix max temp, mix design temp, mix indoor temp based on a indoor design temp of 70.