Residential Equipment
Where to begin: Riello gas burners were the problem child in 2001 and into 2002, possibly longer.
The gas burners, G200 and G400, installed on the Vitola-Biferral and Vitola 200 boilers, had chronic nuisance lockout issues. Some of these lockouts were resolved by servicing the burner (cleaning or replacing electrodes, both ignition, and ionization), yet many were attributed to the Honeywell combination gas valve.
It was decided that we would retrofit these burners with a different style gas train, which included a regulator, a safety solenoid, and a step-opening safety solenoid. This was affectionately known as the Dungs gas train.
History of this gas train: The original components were a Maxitrol Regulator sized for the boiler size (½” RV52 for the G200 and ¾” RV52 for the G400), a Parker valve (incorrect application for this valve), and a Dung's step opening valve with two adjustments, ignition, and full input. The full input adjustment should be 100% open. The ignition pressure was to be adjusted per the Riello Installation and service manual as shown here:
The Parker valve referenced above is a type of valve that requires a minimum pressure to force the valve open. In some cases, discovered during a trip to Michigan after 9/11, the valve would stick to the body and not open since the pressure required for the valve to open was not met. The pressure requirement for ignition is only .7 to .8” WC as noted above. The pressure required to open the Parker valve is approximately 3” WC (inches water column), according to a contact at Parker Valve support.
Many Parker valves were replaced with Honeywell Solenoid valves as mentioned above. One such project, Leisure Acres in Grand Rapids Michigan, had the Parker valves replaced just a week after the gas trains were installed, as seen in the service records here.
It was determined that the appropriate solenoid valve is a Honeywell solenoid, model V8295 (see page 6 of the Riello I&S Manual linked above).
Viessmann Outdoor Reset Controls - Residential
Trimatik II
Trimatik MC
Trimatik RN
Dekamatik HK1 - Mixing Valve Control
Vitotronic 200/300 (KW2/KW3)
What do all the above controls have in common? They are all electronic outdoor reset controls and thus require an outdoor sensor and proper settings of the heating curve to satisfy the conditioned space at all outdoor temperatures.