Dual Knight Boilers (Commercial Install-Job Pics)

and near an elbow or such,
cause the turbulent flow of the water will keep the well clean, as opposed to horizontal mount where lighter than water debris will get stuck in there, the only issue is a leak (which unfortunately happens a lot with these – I stock them) where water leaking into the switch might give you a closed circuit if it’s driving electronics instead of the relay directly (this would the case with the laars endurance (formerly heatmaker) – so they need to have it horizontally – they still fail miserably)

for boiler protection – the most reliable setup I have found – is two 110v LowWaterCutOffs (the 24v failure rater is higher) one mounted high in the boiler room above the pumps (to protect them also) with an auto air vent above it (I use a spirotop)
and one mount above the boiler’s heat exchanger level. AND, a manual reset hi-limit mounted on or as close to the hottest part of boiler’s heat exchange as possible – this eliminates moving parts in the water (the LWCO are electronic and the Hi-limit has a sense bulb – though there are electronic water flow switches – using sound, or blue-green photodiodes, or radio wave Doppler sensing - but they are still to expensive for our use)